All models made during WW2. Prior to WW2, many models have a distinctive "V" shape. Vintage Flattop Gibson Collectibility. Tall numbered gold knob, used from to"speed" knob as used from to"bonnet" knob as used from to"metal top bonnet" knob or "reflector" knob as used from mid to mids on many, but not all models. The Les Paul models from the 's along with the Korina Flying V and Explorer are some of the most collectible solidbody production guitars. BGN instruments weren't acceptable to Gibson as sellable to the public. From to the method of serializing instruments at Gibson became even more random.
Prior to about mid, have small decal on bottom stating "Patent Applied For".
Gibson Serial Numbers
Next to it is the ugliest pre Gibson knob, known as the "amp" knob, used from late to the mid's but not on all models. With vintage Gibsons selling at auction for as much as half a million dollars, Davidson will sometimes roll up his sleeves and poke around in the ledgers, but only as time allows. The war-time list that follows is not definative but includes FONs that I have seen. The number on the left is still a "pressed in" number, though gibson has inked the impression to make it more readable they started doing this about orwhen serial numbers went to six digits. Bridge, flat top models. Gibson invented the archtop guitar as we know it and has remained one of the better makers.