Update... Last night I pulled the front cover and found genuine MB rails and guides. This baby is CLEAN on the inside!! The plastic guides are worn and brittle so I think they're original. The timing and oil pump chains are stretched almost to the tensioner limits so they may be the originals also. Maybe she was still a virgin!!! Thanks for the advise guys!! Benzmac.. Does TBR do an exchange? I'm ready to get on with this!! Santa's coming and needs a way to ride!! I'm only 170 miles away so I could drive up and swap out in just a few hours.