You want to look at the chrome/stainless around the rear of the roof, because there's a few convertible only trim pieces that if missing, will cost an arm and leg IF you can find them.
If the car has buckets, make sure you have the right rear seatback with the emblem. If the rear inside panels are missing, that's another vert-only rare as hen's teeth item.
Check for rust everywhere because those rear quarters fill up with water when the car gets rained on...trunk floors are often rotted out as well as floors themselves. 30 years in a JY is enough to rot any car beyond saving especially a convertible, so unless you want to end up with an expensive parts car, make sure you check every inch of that thing.
Lots of things are easily sourced as well, so if the ragtop stuff is mostly there, then the other stuff can usually be found online, at swap meets or good ol' Year One.