I think I remember that these guns were made by Zabala Hermanos y Compania. If so, they had a website the last time I looked and you could google them.
This is an entry-level gun which is valuable primarily as a shooter. Good news is that if Zabala is still in biz, you can probably get parts for it. It should have a "date-of-proof" code on the "water table" (the flats of the frame that you can see when you take off the forend and barrels). It will be a number and a letter (like B1) and will tell you when the gun was manufactured; if you will email it to me at g.armstrong
hvcc.edu I'll look it up for you.
The water table and barrel flats that mate up with them will have a lot of other info, and perhaps tell you who made the gun.