I used to have a Marlin 120 back in the earlhy 1980's. It was a well-made, good looking shotgun. It was my first shotgun, and my second centerfire. Took my first ducks, with it. I was invited to go deer hunting in western NY (shotgun only area), and did some range testing with slugs. I was impressed with the baseball-sized 5 shot groups I made at 50+ yards (plain jane Winchester foster 1 oz slugs) that hit point of aim with its fixed modified choke.
Overall It served me well. Wish I still had it. Good to see your picture. Nothing like forged/ milled, and blued steel guns with walnut stocks. The Marlin 120 was an underated shotgun-still is.