The 2 pins in the second to last picture closest to (1 above 1 below) punch them out then the plate should come off.
I think it does, I cant remember i know ive already tried it. But when its off it cant hold onto the gun
there are 2 plates, one thats a thinner end and one thats in the photo. Ive tried both View attachment 36934
Punch those two pins out (one side may be a half moon if so hit it so the circles comes out first). Then there's a plate they go through which should just drop out but you may need to put a little leverage on it.