Basically, all samurais are the same between 86-95, with the big exception being fuel injection that started in 1990. There were a few variations/options available during those years (2wds, tintops, different dash designs, softer springs, different wheels, 2 different 5th gear ratios).
All 86-95 samurais had solid/straight axles front and rear.
The 88 vs. 88.5 isn't really a big deal. They just did a few design changes and some mechanical changes (a slightly weaker front carrier in 88.5s and up and a lower 5th gear ratio...which equates to about 300 more RPMs at 60MPH). Nothing that really would make me say that I wouldn't buy one, just because of one of the changes.
If it were me, I would look for one with EFI (electronic fuel injection). So that would be a 1990-95. Problem is, 90-93 samurais aren't real common to run across. And the 94-95s are even more rare to find.
The EFI samurais do have an issue with the ECM capacitors leaking and making the ECM inoperable. But if you get the caps replaced, before the ECM dies, you shouldn't ever have to worry about it. And most can be brought back to life, even after the caps leak and make the ECM stop working.
A tintop would be nice, if you want a little added security and don't care about it being a convertible. Although, tintops aren't nearly as common as the convertibles. And tintops weren't available during the 90-95 EFI years.
The good thing about samurais, is that stuff is easily swappable between most all years. So if you find a tintop and want EFI, you can buy (if you can find it) an EFI setup and wiring harness and swap onto/into your tintop. Another option is to swap in a 1.6 8V or 16V engine (all are fuel injected and have 80 or 95 HP respectively) out of an 89-98 tracker/sidekick. They are very common swaps and there are lots of info and conversion parts out there.
Also, if you happen to find a 2wd, it is easily converted over to 4wd.....you need a tcase with shifter, complete front axle assembly, front driveshaft. The thing to watch for is in 88.5 they changed to a larger driveshaft bolt pattern...so you need to make sure the tcase flange bolt pattern matches the driveshafts. But the good thing is, if you happen to get a "large flange" (88.5-95) tcase, then the flanges can be drilled for the smaller 86-88 dshaft bolt pattern. You can not drill the large pattern into a small flange tcase (at least, I don't recommend it).
Something that is common between all samurais.....rust. They all rust (although southern states and cali ones aren't usually nearly as bad). Usually the front floor boards, the inner fenderwells (front and rear), under the rear seat, are the most common places.