The rubber gaskets at the base of the valve cover and crank cover bolts should be replaced from time to time. It's not really necessary to replace them with the same frequency as the valve cover gaskets however after some years the rubber gets hard and the gaskets can crack, leading to oil leaks. The old gaskets can be cut off with a sharp blade or some sort of cutters. The new gaskets are pliable and easy to push onto the bolts.
Note: These are sold each.
For a K75 Valve Cover you need 10 and for K100 - 12
For a K75 Crank Cover you need 8 and for K100 - 10
Equivalent to 11 14 1 460 934