Friend of mine reproduced the correct screw for these (they came with none) so I can use them now.

Kind of fun, these wacky trigger stop Ropers were built for pre-war long action guns. They make for very very interesting SA shooting on a gun that they were calibrated for (of which I only have one that works exactly right). I put them on my K22/40 with it's a pre-war Long action and I think they may stay here. They fit my hand great with a lot of right hand palm swell, but the trigger stop stuff is kind of annoying. On this gun its very nice though as it's not so precise as to get in the way.