On the back of the T-case, dead center, should be a round metal tag about 2"s in diameter. It will tell you what you have. If that's missing (not usually) you could try comparing it to stuff over on Novak's website..they have a pretty good knowledge base there. There are a few issues you may want to look at as time goes on with your new (yea!) waggy. The 80s were not a great time for electronics and vaccum stuff. Emissions being the strangle hold it was there are a lot of poor quality and near useless junk attached to these. If your front axle has a CAD type system you may want to start replacing vaccum lines or think about going to a different t-case. Since your dealing with a vehicle that is 26 years old, there is a good chance a lot of those lines are brittle and/or cracked. Between the motor and the 4x4,Heater, etc... there are a lot! If something stops working don't fret...that may be the likely cause. If you can find one, there is an NP208 that should bolt right up and is an all manual t-case. That doesn't do anything about the front axle but will be a less complicated system.
Also, check all the electrical stuff under the hood. They have been known to develop Car-B-Que if the wires get old/rotted.
You'll find the rear window is a PITA sometimes. They are very failure prone. Check all the windows rubber "sweeps" to make sure they are soft and compliant. As they dry and get hard they make it difficult for the windows to work and eventually they break. If your's has electric seats you may want to pull them and clean and lube all the tracks and moving stuff.The seats are pretty heavy and when they get gummed up they break easy. Expensive to fix but easy to prevent.
We need PICTURES!!! I want to see how he fit 35s on with just 2.5"s of life...I think maybe your mistaken. heehee! The front isn't so bad but the small rear opening requires more lift/trimming to ever hope to get 35s in there.
Glad you got it and welcome to the FSJ madness!