Given the demand for just about any kind of raw materials for use in WWII, I wouldn't think to heavily toward the wood from a 62 banjo being from the 30s or 40s. I would say anything is possible though, especially with Gibson. I have never heard whether wood could be dated or not. Maybe someone who knows will chime in. Good question.
There has been this same discussion numerous times. If someone cuts down a mahogany tree today, the tree could be be 350 years old, so looking at the cross section of the trunk, the wood in the center will be 350 years old, halfway out it will be 175 years old, near the bark it might only be 10 years old.
As far as I know, lumber is not graded by what section of the trunk it's cut from, and does it make any difference?
Honduras mahogany has been cut pretty well constantly over many decades or even centuries. I guess the Cuban mahogany was pretty well gone by the 40s, but Gibson never claimed to use that.
I imagine all of it is/was "old growth" as already mentioned above. But how long it had been in Gibson's timber yard, or even cut into planks and dried, is probably "relatively shorter" since WWII than it was prior to. I agree, it is doubtful any wood in Gibson's yard from the pre-war years, survived into post war banjos (or guitars).
Again, dry is dry, so once it IS dry, I don't suppose it makes an awful lot of difference how much older it might be than that.
Gibson was and is a MANUFACTURER not a craft shop with old bearded dudes whittling instruments.
Prewar banjos were made from wood harvested and dried commercially likely used within a year or so of felling. Same goes today. One of Saga Musical Insteruments claims to fame during the eightys with Gold Star banjos and Kentucky mandolins was Richard bought wood from the same supplier to Gibson during the prewar days. Cut and kiln dried just like then
The war effort used all available stock of materials for ALL companies making anything