Pre WW2 Spain did produce a few revolvers that had a good reputation. That apparently is not one of them. If the maker had any sort of reputation, it would be branded. I myself would not try to fix or fire it, either. Has no colletor value whatsoever and the only way it would have any value is if it were associated with some notable person or event. Sorry. Well it is an heirloom, those may only have value to the recipients but that is enough I suppose.
Your gun is like your nose, it is just wrong for someone else to pick it for you!