I've got a 1980 242 with the manual crank sunroof, after closing it one night I realized one of the back corners of the panel doesn't raise back up to sit flush with the roof when closed. Haven't been able to find anything on this anywhere

 

Most commonly the cables get "out of time". Can be a 2 minute fix>
Mostly close the sunroof - stop when that first corner is about to flip up.
Take the sunroof handle off, take the sunroof gear off
At that point you should be able pull the sunroof open and push it closed with your hands (with the gear removed) Pull it back slightly and push it as far forward as you can. That should align the cables.
The sunroof gear only turns so many turns in each direction, so back it up a turn or two (the gear slips on the cables easily and you end up at the end of the gears travel with the sunroof not closed sometimes)
Reinstall gear, and handle - try to close sunroof all the way
If closing is still not even - repeat until it is. You might have to use a screwdriver to push a cable a tooth or two with the gear out.

If the cables are aligned and one side still does not flip up - you will have to replace one or both cables. When closed the height of each corner is adjustable - you have to unclip the headliner (row of clips on the front), push it back to expose the 4 sunroof mounts - there are adjustable nuts that control the height of each corner. Or if a cable is broken, you can push the headliner back and wedge the right size block to hold the sagging corner up to prevent massive water intrusion.

On a 40 year old sunroof - if you get it closed (check the drains to make sure they are clear first) leave it closed.

 

Alright I'll try to fix it tonight, just bought the car a couple weeks ago, sat for 18 years and surprisingly the sunroof was the only issue I really ran into