Shouldn't stick.......that's what I thought too. Even with the release agent on the blue painters tape, it still stuck. As I said, it's not a huge issue but makes the clean up a little more time consuming. If you're really worried about residue from the masking tape, put blue tape on the stock and masking tape over that......then release agent.

I've never used blue tape on the recoil lug so can't comment on the effects there. I wouldn't chance it with devcon though.