I dont think there is a actual revision, though they did start making them tougher about 5 years ago now. You just need to ask for a cam follower for the TFSI 2.oL engine. Any Audi or VW dealer will supply. It looks like a ickle thimble, the top part takes a battering, and in severe cases disintegrates sending metal around the head and sometimes throughout the engine.
If you look down this page there is a picture of one that has given up the ghost. The guy had to have an engine strip down and clean.
http://www.mk5golfgti.co.uk/forum/index.php/topic,22082.225.htmlThis is very rare though, lots of modified engines on here and no more than a handful that i can remember having catastrophic failure. Hundreds in the US though.
If you get it checked on each service you will be fine.