Hi, Bill:
I'm sure gluing is a viable option, although I've never done it. I had one gun where the owner wanted the LOP shortened until we found out the pad had been glued on, then he changed his mind and left it alone. I'm not sure of the need to glue a pad on, as I've never heard of one slipping; maybe it seals the end grain of the wood better than stock sealer, I don't know.
Craig