Hey Chaz, you will have to take some comments posted here with a grain of salt. Of course, if you loved the gun and you wanted to have it as perfect as possible you could fit a new pin or weld the hook or whatever. But for your purposes soldering a piece of shim stock is the way to go. If you use a glue you will always be expecting the shim to fall out so stick with solder. Really any solder will do, whatever is handy. I made that comment about lead-free solder because I had to do a bunch of copper sweat joints recently and it's not as nice to use as the old stuff. I swore a lot. Anyway, if you do a nice job your heirs will still be shooting that gun when you are six feet under.
Nial