The gears look fine, they aren't sharp, and don't seem to be hooking, but then again the picture is dark and not very large. That said, it may not be a bad idea to just replace everything, kind of the "do it right the first time" approach. I wouldn't fret over the profile gasket too much, but if it makes you feel better, then do whatever you would like. I would certainly repalce the chain and rails though, and throw in a new tensioner when its all buttoned up.