It obviously was in need of a tune-up a long time ago. The bolt is leaving serious drag marks on the cylinder that show it's releasing way too soon, and I suspect that it isn't carrying up correctly as the cylinder turns from one chamber to the next. It also seems to be worse on one side then the other, which is a clue that the crane barrel (on which the cylinder rotates) is bent.
It is a neat gun, but putting in back into shape could run anywhere from $100 to $200 and maybe more. Serious collectors are unlikely to jump because it has lost too much of the original finish. They will sometimes pay big bucks, but only if the piece is in like-new condition - both in terms of finish and mechanical condition.
The Old Fuff loves these older Colts, but anyone who is thinking of buying one in this condition should have it checked out by a qualified gunsmith (that are hard to find now) and if work is needed get an estimated cost. Be aware that the factory probably won't work on one because they no longer have any parts.