I acquired an old Winchester 120…
Wow, that caught my attention… with the years of production being from 1984 thru 1986 for the Model 120, I'd hardly consider it an "old" gun. To us graybeards, an "old" gun was made before WWII, or earlier. Of course, with Winchesters, some use "pre-1964" as a more recent benchmark. That was the year Winchester made drastic changes to modernize their production techniques. And, 'Chesters made after 1983, like the 120, can be considered "new" guns because they were made after US Repeating Arms took over Winchester.
When Winchester came out with their new line, in '64, the 1200's V-cut at the stock/receiver joint looked dorky to me. Because of that, I've been prejudiced against them ever since. With a straight joint, you can typically tweak a stick gun's stock with a pinch of woodworking -- with Winchester's V-cut, it's a lot more complicated, if not impossible. The factory engineers will probably claim the V-cut receiver is a quantum improvement.
(I once bought a tubed shotgun for a pittance, because the "barrel was bent". NOT - The prob was the choke tube was machined a tad offline with center, throwing the charge Waaay off to on side. New tube = new gun @ full price )
Congratulations, a knowledgeable used gun buyer can get great deals. Briley used to sell (may still) an off-axis choke tube -- custom made to correct errant barrels. I'm guessing, with one of those puppies, indexing the tube was paramount.