Hey Bob, The magazine catch he has is a type 3 with just the m on it meaning the modified type to fit and slide easier in it's slot as it's thinner.

The Q on the slide could be anything from an inspection mark to someone at a plant just messing around.

Now Charlie, I gaze into your future and I see....Nothing. Nothing but WHITE!!!! Endless hours of SNOW!!!!! Enjoy it every flake of it. Oh Yeah.