The shipping dates quoted on this site are, for the most part, based on the serial number index included in Joe Spann’s book, Spann’s Guide To Gibson 1902-1941 (published by Centerstream). Joe explains that while the FON (Factory Order Number) is the best indicator of when an instrument was manufactured (each prospective batch of instruments was assigned an FON before production began), the serial number relates to its shipping date.
“Serial numbers are not a good indicator of production date because many instruments that qualified for one did not receive it until final inspection, just prior to being shipped,” he says. Joe defines ‘final inspection’ as: “stringing, casing and placing of paper serial number label.”
In the case of instruments produced prior to 1930 however, Gibson researcher Darryl Wolfe (founder of Darryl Wolfe’s F5 Journal) disagrees to some extent. “While Joe’s serial number list is generally correct for the later 1920s, 1930s and 1940s, I believe that when it comes to the period of 1924 to 1929, there were some gradual changes that eventually resulted in serial numbers being assigned at shipping.
“In the 1920s and even prior to that, the serial number was added after the FON had been assigned to a batch and instruments in that batch received serial numbers as they became ‘whole’, but before the instrument was totally complete, i.e. NOT at the point at which it was shipped. When labels were applied, the serial number had already been written inside the instrument at the point at which, say, the top or back was glued on to complete it as a unit.
“For example, guitars comprising a batch of L-5s with the same FON may have been shipped out at different dates – perhaps as much as several years apart. This resulted in instruments where three may look one way, while others could have fingerboards, finishes and hardware that do not conform to a specific era. In short, manufacture of an instrument shipped in 1930 may have begun in 1925 and that instrument could have been in any stage of completion in 1925.
“L-5 serial number 81629 – which according to Joe was shipped in 1927 – is a perfect example. It is roughly 1000 numbers after the last Loar-signed L-5 in late 1924. In my opinion, this guitar was nearly complete in 1925 and reflects identical details to the 1924 versions except for a lighter sunburst finish and gold parts. It is inconceivable to me that the serial number was assigned in 1927 and that Gibson had only made 1000 instruments in three years. That would relate to a 95 per cent cut in production!
“Another great example involves the very last Loar era F-5 mandolins, all of which have the same FON batch number – 11985. Serial number 79836, which was signed by Loar on December 1, 1924, is part of a sizable group of consecutively numbered signed and dated F-5s. A second, smaller group of F-5 mandolins were signed on the same day and have the same 11985 FON. These are serial numbers 80416 and 80417. Finally, a third group of mandolins with consecutive serial numbers occurs at serial numbers 81250-81268. This last group is not signed by Loar. All of the above instruments are essentially identical, with flowerpot inlay (not ferns) and all possess the same FON. They all have the same period-identifiable binding type and the same very dark black finish colour around the edges.
“One could argue that the above examples support Mr. Spanns’ case, i.e. that the serial numbers were assigned later.
“Mr. Spann’s information would seem to indicate that all of the mandolins were built in 1923 (according to FON’s) and all were shipped in 1926 and 1927 (at which point the serial number was added) despite the fact that most of them were signed and dated by Lloyd Loar in late 1924, just before he left the company. To me, this just does not add up – especially since some of those same mandolins are pictured in Catalog O, which is assumed to date from late 1924 or 1925. My theory is that they were closed up (the back and front fitted) at three distinct times prior to December 1, 1924, receiving three groups of serial numbers as they were completed and that they were all bound and varnished at the same time prior to December 1, 1924. But only the first two batches were strung up for final fit and quality control approval. These received the last Loar-signed labels and their Master Model label bearing the serial number that was written inside. The third group hung around Kalamazoo for a while – with serial numbers written inside them – and were later strung up and, since Loar was no longer there, did not receive a Loar-signed label. Would any company place a label in an instrument bearing the signature of a person who was fired or quit, especially with a date on it that was three years old?
“So, my entire argument boils down to the fact that an instrument that was shipped in 1930 does not indicate that the serial number was added at that point. In my opinion, the serial number was more indicative of when the instrument was built. This began to change and gradually became more indicative of when instruments with a similar serial were being shipped
“Again, my thoughts primarily apply to higher-end instruments that sold much more slowly. My argument gradually goes away the closer we get to 1929 and 1930. At that point, it appears that Gibson had fully shifted to building in small batches to meet existing – instead of anticipated – demand. From that point on, the serial numbers align far more with the shipping date.”