Its a 25 proofed at eibar in 1928 likely late in the year because of the b date code as well as ringed p (they switched to the ring p in dec 14 1928 I believe though most sources say simply 1929).
The slide simply says pistol automatic but there does look like a makers trademark on the frame but was drilled though for the grip screw. I can see only a small section of it.
Any one ever seen these grips before? Don't worry I know its not worth anything.