Thys
I replaced timing belt and cover on my 300TDI a couple of months back,and yes the original outside seal appeared to have a metal bush through it.I replaced mine with a normal looking seal ERR4576GBut was advised if they are still in one piece, to leave it alone.I guess my replacement will not last as long as the original,just have to make sure timing drain plug is removed asap after wading.
Cheers
Geoff