Any time you drill a hole of any kind in a "mint" gun you just kill it's collector value.
I know it sounds crazy, but put if you put them on GB with good pictures and good description and start them at $.01 for 14 days you are going to do as good as you can do. Everybody in the world can see them and all it takes is 2 guys on the whole planet that want the gun and it can bring stupid money.
I know cause it's happened to me, many times.
BTDT as well, only I was the seller. Stupid is as stupid does and once egos start getting butt hurt, the one with the biggest wallet wins. I'm sure they wake up with a throbbing headache in the morning too...