I’ve been trying to make some sense out the relationship between serial numbers and factory order numbers (FONs). I wrote about these mysterious numbers before and was more confused than enlightened by my research. So, I’m putting them all into a spreadsheet and trying to make some order out of the apparent chaos. I’m only going to look at 1958 through 1961 since those are the only years relevant to ES 335/345/355 guitars. They stopped using the FON in 61, so we don’t need to go any farther than that. Here’s what we know about them. They are sequential. They begin with a letter which designates the year (going backwards in the alphabet from Z to Q which is 1952-1961). Following the letter prefix was a three or four digit number known as the “rack” or “batch” number. I’ve read that they started at 1000 and went through 9999 and started over again. I’ve also read that they started at 100 and, until recently, I never saw a three digit FON but now I have . Among the guitars I have catalogued, shortly after FON S9xxx is S6xx and shortly after that S9xx. So, it appears that they actually do go back to 100.
What is most important about these numbers is that they represent the beginning of the process of building the guitars and not the shipping date which is really what the serial number and Gibson shipping logs will tell you. It really depends on how much information you actually want or need. Mostly, it doesn’t really make a whole lot of difference whether your guitar was built in July and shipped in August but for low volume models, the FON can tell you a lot. That’s because the amount of time that may have passed between manufacture and assembly and shipping could be years. You heard right. Years. It’s not common for ES 335s to have sat around waiting to be sold since they were always pretty popular but models like ES-350s and Byrdlands and ES-5′s could have a very long wait between the build date and the shipping date. There are notable exceptions. I recently sold a 335 with a ’62 serial number but a “R” factory order number. “R” designates the guitar was built in 1960. It has some odd finish issues so it may have initially been rejected and used later. This is the kind of stuff I’m trying to figure out. Another good example is a mono ES-355 I had with the serial number well into 1959-A30659. But it had a FON that began with “T” making it from a ’58 rack. Interestingly, it had a huge 58 like neck and the thinner top of a 58 build. Most 59 ES 355′s have a fairly slim neck (unlike most 335s and 345s). Granted, this is something of an exercise is minutia but I have nothing better to do today (it’s cold, it’s raining and it’s Sunday-and I don’t like football). FONs are particularly useful when a guitar is on the cusp of a transition-like an early 60. Even if the serial number indicates a later 60, the FON may tip you off to some earlier features. My ’60 ES-345 TDN had a January serial number but it had an “S” FON so I know it was built in 1959. That made it more desirable to my buyer and it justified the 59 knobs and transitional neck profile. The conventional wisdom in dating these guitars is to use the serial number-I get that. But I think the FON will be more accurate in predicting the features and measurements and give you-the player, the buyer, the collector-more ammo when it comes to buying a guitar sight unseen.
So, PLEASE, if you own a 58-61 ES-335/345/355, email me the serial, the FON, the model and a short description. You and your guitar will remain completely anonymous. I will publish the database when I reach around 500 guitars. It will only note the serial, the FON, the model and a few features (stop tail or Bigsby, etc. or anything unusual). You can email me at email@example.com. And thank you.