When I made my first reply, I had a feeling that perhaps I should check my examples to see if they have the bushing (a bushing that would seem unnecessary). My instinct was right. Apparently, ALL Model M pistols have the bushings! All of mine do. (Why Colt thought the bushing necessary remains a puzzle.)
On the offending pistol with the loose bushing, I would knick up the outside of the bushing to raise some metal and drive it back in place, perhaps with some red Loctite for good measure.
(Apologies to anyone offended by my "delivery.")