In Smeck's time and even up into the 1960s, it was often cheaper to use solid wood than plywood, especially with small instruments. Until fairly recently, "genuine mahogany", that is Swietenia macrophlla (Honduras mahogany) or one of the other Central or South American mahoganies, was no big deal. It was relatively cheap, very plentiful in very large logs and boards, and very easy to work.
And as Mr. No Man points out, endorsements went to the highest bidder. Probably the most successful endorser of all times in the music industry would have to be Les Paul...who did not design the guitar bearing his name nor the most commonly used pickups for them. He got paid...very well...for a signature for many decades.