Yamaki classical guitar GC25

This old guitar is in outstanding condition, it shows wear from use, but no abuse. I have found limited information on Yamaki guitars, but haven't been able to find anything about Yamaki classical nylon string guitars. I would appreciate any help to provide information about this guitar. Is it rare? Is it of any value? Any history available on Yamaki classicals? Age? Since I took these pictures I have restrung the guitar and it sounds wonderful. I am hoping that I finally found a treasure.