I have a 1965 B20. I also have a few other guitars, but this old Gibson is the best sounding and my go to guitar. I bought it from my neighbor, who purchased it at a pawn shop in Nashville in the 70s'. The sounds is rich and full and no one can believe it comes from a such a small instrument. The model is stamped in red on a felt tag inside the the guitar and can be viewed though the hole. How unique are these guitars?