I have a double barrel 20 gauge ugartechea shotgun I'd like to find out a little more about. Got the gun in the mid 70's from a guy who owed me a little money. Shot it a few times, not recently, and seems to be a very nice gun. Know it's Spanish made but can't find a model name or serial number. Only the Ugartechea name and that it was imorted for sale in the United States by some outfit in San Francisco. I've seen online some are fairly expensive guns. Any info would be appreciated.