I've never used a steel shim to put one back on face, but I do use a homemade shim of adhesive backed aluminum duct tape, as used in the HVAC business, on my "much used with heavy loads" BSS. It will last about 300 openings and closings, then I just remove it and replace it. The kind I have measures .003" with the backing sheet removed. Easy to wipe the hook clean with alcohol, let dry, stick on a piece of the aluminum tape, then trim to a perfect fit with a sharp Exacto knife.
Shimming, with whatever, is never the proper way to put a nice gun back on face. But for one that you may or may not keep, or for a non-collectible of low value, I think it's a good temporary repair.
What did you plan to use to hold the steel shim, Loctite?
