IIRC others (and myself) have found similar wear from that spring. In my 80 it wasn't worn all the way through yet. so it may not be un-common for the plastic to wear from the spring pushing/grinding on the thin plastic wall.
You might could fix it with a piece of metal (or metal mesh) and...
Did you hook the actuator back up to the harness to see if it moves when you press the door lock/unlock button?
Were the small arms all attached? All plastic clips that hold the small arms
to the lock mechanism intact?
If the actuator doesn't move at all you could try a search for door+...