SeaBass: I can't recall if they are the advanced technologies mounts or not but if you are referring to the no-gunsmithing mounts that replace the rear peep sight on the #4 Mk1 SMLES and go through the loading bridge, then yes, they work and hold their zero.
I've put a couple on some SMLES I have. I have switched one between two different #4s and it now rests on my older Savage made WW11 1942 production sporter (and groups 3/4" at 100 yds)(that's sub-moa, isn't it??), but they do hold their zero. I put one on a #1 Mk3 and did not have any problems with it.
One trick to consider is that there are two holes in these things: one is used with the rear sight pin to hold the mount in place at the rear and the other, drilled and threaded from one side to the other is near the other end. That later hole is where the set screws go to hold the mount firm against the inside of the loading bridge - what you need to do is dimple the place where the screw impacts, or the scope mount will ride right up on ya and you'll be looking at the birdies while trying to find the 100 yd target. It is real easy to do as the metal on the inside of the bridge is soft - just get a small enough drill bit so you don't screw up the threads. Then, locktite the whole arrangement and you are in for some shootin' fun. HTH. Mikey.