I have a spanish military pistol with the following markings: Automatica Espanola-Pats 62004-67577, Bufalo call 7.65, serial no. 3516 and has buffalo head emblems on pistol grips. It is in excellent condition.
I could be wrong, but I believe I have some info for you. I hope this helps:
Gabilondo y Cia manufactured Buffalo pistols from 1919 to 1925. The pistols were marketed by Armeria Beristain y Cia of Barcelona Spain. Buffalo pistols were copies of the Browning model 1910, with a concentric recoil spring. Unlike the Browning, they used an internal hammer instead of a striker and had some other minor differences in the internal lockwork and grip safety mechanism which Beristain held patents on. In 1925, the Beristain patent expired and thereafter the pistols were marketed under several other brand names. Unfortunately, these don't have much collector value