Most of this stuff will help you on the business side of the equation only- sort of a "Consumer Reports" for old mandolins.Hopefully, this will help you to determine to what extent the dealer is trying to sell the instrument at a level above what it may merit, and then you must use the market to help determine a price.
Just don't make a profit from it without giving me 87%!!
The Gibson Company went through several stages of model design for their mandolins in the last 100 years.
I recently discovered that this photo of my Great grandfather's Mandolin Orchestra appears on page 21 of the Gibson "M" catalog, published in 1921, confirming my theory that he (Joseph L.
Ivers) was a Gibson "teacher-agent" or dealer, and that this photo was part of the "Everyone a Gibsonite" marketing campaign.
Like all instruments manufactured by Gibson, their mandolin's are constructed with only the highest quality materials and woods.