If I own a 1993 Sammy that is 2WD and I want to put a 4WD transfer case in it does it have to be 88.5 or newer?

Your life would be easier if you pickup an 88.5 or later, it will have the large flanges that match your existing drive shafts.

If you get an earlier one, you'll need to get creative with flanges. Two choices:
You can replace the flanges on the transfer case.
You can mix and match parts between a set of small flange drivelines and the ones you have.