Guy has a 20 ga double F/S marked Universal Firearms. Blue book says $300-350. Anybody know if this has decent steel for conversion into a 45-70 DR? Has Greener cross bolt, but photo looks like high school class engraving.

I don't know that brand, but I know that a lot of really cheap (and I don't mean inexpensive) shotguns were imported from Spain in the '60s and '70s. I wouldn't chance it. If nothing else, I wouldn't put that much work into a gun with cheap small action parts, which many of the Spanish guns of the era had.

The Laurona guns that sold in Sears stores under the Sears brand name were pretty well made, and sell for the same price. I would try to find one of them, in that price range.