Hey Matthew,
If the suit is a rear entry it is not a Catalyst Classic but probably an Aqua Pro or Nexus. The Catalyst Classic only came in front "shoulder entry" I have an old customer cut Classic that has well over 1000 dives on it and it's still dry.
Things to look for, wear on the attached boots, heal and attachment points, zipper condition, and seals. If the zipper is worn, has broken teeth, or leaks and is on it's way out you may want to reconsider this purchase. Zippers are pretty costly to repair, and pending what you paid for the suit it may not be worth it.
I hope this helps!
Cheers,
-Dive Dry-
