Welcome to the forum!
I look forward to the day when I can refer to myself as "that retired guy"... ;)
Unfortunately, usually when your state is that willing to look out for your welfare, they generally frown on you opening things up and modifying them yourself, too.
If you were to do this the likely "approved" method would entail getting a follower with "legs" on it that would keep the evil extra round out of the mag, thus rendering the firearm perfectly safe, of course. I'm not sure your keepers would approve of you just gluing a piece on here or there, which could then be un-glued, or (gasp) fall out. If nothing else you might find yourself in the uncomfortable position of trying to explain to the nice Deputy, or Fish & Game guy, that he really doesn't understand the law and that your gun is perfectly legal, despite what he thinks.
(No offense meant of course; I'm an escapee of MA, so am just going with the whole totalitarian regime thing...)
-- Sam