Time to share a slightly embarrassing story. 4-5 years back I decided to try a red dot on a pistol and saw a Modern Sportsman auction on GB for a complete G41 MOS slide assembly without the plates. So I ordered a set of plates and started bidding. Won the auction for a pretty good price, picked up the slide and realized that it was not MOS but a direct RMR footprint. Not having a red dot picked out, I returned the slide… then few months later ended up buying a Holosun 507C with the same footprint