I can say that drz cam chain fits 100% on my FSE450 from 2003. I replaced my tappets with OEM but I'm 98% sure they were the same size as my DRZ's (I own one of those too). Maybe look at getting parts form somewhere else because I only paid $80 for each tappet and DRZ ones were $112 each
I bought from Scotties Dirt Bike Spares in Melbourne Vic Australia.