Hi Mike, I can find no mention what so ever in any of my reference books on this marker(s). This leads me to think that either it was a small shop or a guild sort of gun.
I think you may already now that with early Spanish guns, looks can be very deceiving. At times much of the work was done for outside appearences and the "guts" of the gun took the short end of the stick. This is were the old saying of "soft" steel came from. Spanish steel when it is properly hardened is some of the best in the world. Herein lies the problem, lots of times the steel/metel was not hardened, hence problems.
The old saying "Judge the gun" really applies to most spanish guns of the 50's, 60's, and 70's to almost today. Even the "big" makers turned out junk for some of the importers. Built to a price point and that was it.
That being said, I'm not at all saying that these guns are junk. Many of the small concerns turned out guns that would give an english best gun a run for the money.
Thats my 2c worth. I hope someone else with experience with this maker can chime in.
All the best!
Greg