They actually work rather well:
This one has been rock solid for me, and looks slick:
Ruger Mark IV 75th Anniversary lower, Volquartsen match-barreled 4.5" threaded upper w/Volquartsen accurizing kit, Crimson Trace dot on a RedDotMate Docter/Noblex base. The base was $28.81 to my door & very nicely machined & finished, with a good selection of screw lengths included. Ships from China, though, taking about 8-10 days. They offer _nine_ different dot footprints in this unit. I plan to order one or two more.
I like buying American, too, but with US-equivalent models costing from $35-$69 plus shipping and sometimes tax, you can't beat this one for performance and value. reddotmates.com, and the guy was extremely responsive to questions as of Dec. 2025. They offer adapters for a surprising range of different guns.
The only downside to the rear sight replacement mounts is that removing the Mark rear sight can sometimes be a bear, given the cylindrical receiver being hard to get a good grip on without damage. In the old days, most dovetails were tapered so that you removed the sight from left to right, but the Ruger Mark dovetails are cut straight through, with both some friction fit and the two rear sight locking screws (one in older models) holding it in place. The well-known Sarona Gun works guy, now deceased, said: "The Ruger Mark rear sight dovetail slot is milled straight through, so it's the same size at each side. Doesn't matter which direction you drift it out. I've done it both ways, just to prove a point. Don't forget to loosen up the hold down screw though. :shock:"
Highly recommend a non-marring punch, preferably hard brass, and some duct tape on the side of the sight and on the receiver just below the dovetail just to be safe. The duct tape is a must if you can't resist the temptation to smack on it with a steel punch.
Paraphrasing an old adage about marriage: Smack in haste, repent at leisure!