Help!! simple distributor cap gasket question 87 300e, need answer quick!
 

I am in the middle of replacing my distributor cap and rotor, and I am not sure where to put the gasket. The only place I can see is behind the cap itself in between the cap and the orange plate, called a dust cover in my manual. There is a black ring around this plate, but it seems to be part of the plate and not a gasket at all. When I try to remove it it seems to chip. My urgency is a result of my car being in my girlfriend's dad's parking spot, and I need to be out of there before he gets home. As always, all replies are greatly appreciated.

I don't recall there being a gasket in there. Seems like there is an o-ring around that red cover.

Just refreshed my memory by looking at the pictures in Fastlane. The gasket is the o-ring and it fits in the groove on back of the distributor cap.

After looking again, I decided to just leave the old black ring there and put the new cap on. The inside of the cap and that plate were fairly clean inside, so I figured the gasket was probably still good. Thanks for the input Cap'n.

That is one of the ways to tell if an oring needs to be replaced.