There is always lag time between when the patent is applied for and when it is actually granted.
Because parts need to be used up, parts made during the patent pending time period, could have been used on instruments after the actual patent is granted.
Hey Zach, I have a Gibson Les Paul I’m trying to identify.
The serial number is 676323, and “Made in USA” is stamped below that.
They should be used in conjunction with other identifying factors such as serial and model numbers to help to correctly identify your instrument.
The source-date code is usually comprised of a 6 or 7 digit number.
Codes on pots and speakers don't start appearing until after WWII.
Remember that a patent pending notice will pre-date a patent number.
In a 7 digit code, the fourth and fifth digits indicate the year of manufacture. Amp speakers tend to keep the 6 digit code after pot manufaturers made the switch to the 7 digit number.Sometimes there is a space after the first 3 digits, sometimes a hyphen.If you have an instrument that you suspect predates WWII don't be alarmed if you can't use the pots to aid you in instrument identification.Electric guitars and amplifiers can be dated by the coded date located on either the potentiometer sides or back, or the rim of amplifier speakers.Patent numbers can also be used to help in instrument identification.
I was told to check the potentiometer date codes, which all have “1377142” impressed into them.