Originally Posted by T-Mar

Glad to hear that it only a cosmetic issue. Prior to coming out with the full SLX tubeset, Columbus developed the SLX style seat tube to mitigate the issue of front derailleur hangers being ripped off SL tubes. So, it could also be an SL frame with just an SLX seat tube (which could be original or a replacement). The way to tell would be to examine the BB ends of the chain stays, If they have the helical ridges, it's an SLX fameset with an SL down tube, if not, then it's SL frameset with an SLX seat tube.