the 93's have an ECU part number of F37F-12A650-XX, where the XX are different letters indicating things like auto/manual transmission, cali/federal emissions, etc.
94's have a similar F47F-12A650-XX part number.
I can really only use a 93/94, 91-92 and 95 ECUs are completely different and would probably be sent back and my core charged again. It wouldn't matter which numbers the 93/94 ECU had, since they seem to refurb and reprogram them, the one I bought had a different part number originally but was reprogrammed to be a F47F-12A650-CMA.
It would be great if you could check, but so far, junkyards want more for an ECU than the $45 core charge, obviously not worth it. It's really only worthwhile if the ECU is either a junker for free or just a few bucks, sticking it in a flat rate envelope is ~$5 shipping, too.
At this point I'm not even sure if the core return is only possible for 30-45 or 60-90 days. Guess I should call and ask.