@SNAFU22 Thank you very much for those photo's !
They are of a newer version of the catch than the more curved Mk1 model, but functionally they should be very similar.
There is a small vertical projection, or pin, in the sliding cover itself that I haven't seen before.
Haven't got a clue what that is for, but I assume it is some kind of improvement.

'Stamping' text or symbols on/in 3D-models is no problem at all.
Hey, I could do some nice scroll engraving with gold inlays and a hunting scene on the sides of a Bren, there's plenty room for it : )
Here's an example of a roll engraving on an old Smith&Wesson revolver I've modeled recently:

For this I just need a good image, from a photograph for instance, so I can convert it to 3D geometry.