There are two cam revisions, A and B. The A cams supposedly received incorrect hardening. Having the B cam reduces the risk of wear, but having the revised cam does not make you immune to the issue either. Volkswagen has issued a TSB for it and if your engine is affected, they will replace the cams, fuel pump and follower with updated parts as long as you are still under the warranty. If your car is affected, symptoms include a possible check engine light, fuel cuts, and loss of power. Some dealers will not check until a check engine light appears.
The 2008 and up GTI has a revised engine known as the 2.0 TSI. This engine uses a roller follower for the high pressure fuel pump and the issue is no longer a problem.
Cam follower information links: