Does the dial face ie the part with all the numbers etc on it look as if it has lifted up. The face is held down with double sided sticky tape. It may have lifted and the face might be sticking the needle. The needle it's self is driven by a motor, check your connection to the dials is pushed all the way home. TBH I've not heard of anyone having a problem with the rev counter. If you can't see anything that's obvious then ask around and see if someone is willing to swap clocks. At the least you'll find out if the problem is with the clocks or elsewhere.
Sorry I can't be of more assistance mucker.
Good luck and a hope yer get them sorted.