If you aren't going to rebuild I myself wouldn't use any kind of flush/cleaner in it. It would probably break up all kinds of old grease and grime build up in there and start clogging things up. Just run it and get it nice and warmed up then let it sit long enough that you think the oil has all drained down and then change it.
No need to change oil pans this way either til you are ready to tear it all down. Now this is just my opinion, others might have a different idea.
As for the diagrams at the dealer, who knows. This was way back in '84 so the car really wasn't that old at that time.
Where abouts are you? I was in the burbs of Frankfurt. Can't remember the town name but the other little area was Preungeshieme and I know that isn't spelled right.

I can tell you my old address but for the life of me can't remember the village name. hahaha
Oh and not a bad looking Gal.
Deb