I used to own a USFA Lightning. It was in .45 Colt, so it had some issues. Still, it was the most exquisitely-machined rifle I've ever owned, and I've wished many times that I'd investigated the feeding issues more before selling it off. At the time, I was just too afraid to take files and stones to it, though I've since become convinced that I'd have been able to get that rifle running great with some adjustments to the ejectors.
I don't know if your non-shooting cutaway would sell for as much as an intact one would, but its rarity alone should bring a high price. USFA didn't build that many lightning rifles, so I wouldn't be surprised if yours was the ONLY factory cutaway extant. I traded last year for some in-process USFA single action parts. I know that mine aren't the only ones out there, but I value them highly just because they show how much machining went into the USFA guns, and these are guns that aren't made anymore. I wish I was in the position to offer you what that rifle is probably worth.