I’m only just getting started with dots but I’m using loctite and witness marks on the tray screws for both my EPS Carry dots. One of them lost its screw before I even shot it - I don’t know if that was because it never had one, I lost it when unboxing it or shipping it off with the slides, the milling shop lost it, or I lost it between getting the slides back and noticing it was gone prior to the first range trip, but it was still gone when I was putting Duracell batteries in as part of range prep.
My plan is spare screws, loctite and witness mark, and being thankful for an identically equipped backup gun.