Daniel, I have an '87 and (thanks to Gary!) recently swapped out my drivers side retractor for one from his Aeronose donor half of a truck = "Huck"
With the Bricknose '87-'90 trucks the plunger hole looks like a clutch drive screw.
Basically a round center with two 'wings'
Also the lower rear of the door jamb is raised and flattened so that plunger will contact the lower rear corner of the door.
Kind of outside of the 'body' of the door radius, where the inner and outer skins are close together.
I will get a pic at lunch, if it is not raining too hard.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.