A tanbark sail is not going to be an original Catalina sail, that's for sure. sounds like a bargain basement cruising sail from an offshore loft. Doesn't make it a bad sail but without seeing it properly hoisted it will be hard to say from here!
If the boat is new-to-you, try it out for a while, be sure you have enough luff tension when hoisted (some of the crinkles should come out). It is possible, though, that the boltrope has shrunk and is distorting the luff... if that's all the problem is a sailmaker may be able to correct it - just be sure that the sail is worth spending more money on first.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)