Make sure you know what you're getting. Around the '94 & '95 year models New Process changed the input and planetary gear pitch. Slightly different from old to new, barely noticeable to the untrained eye and they won't mesh with one another. I ran into the same issue with our swap. I had to use the front of our 249 case with the rear of the 242 case because with the different gear pitch, I couldn't simply swap out the input shafts and call it day. I know you're wanting this for a crawl box, so this may or may not be of any concern to you. Here's a pic showing the difference.
This is true for the NP242 & NP249 cases, and may or may not also be true for the NP231. Just food for thought.
Copied from another site that I researched when doing the 249/242 hybrid t-case in Wendy's ZJ:
Rule of thumb is cases with a build date of pre 94.5 will have the old style gear cut, and cases with a build date of post 94.5 will have the new style gear cut.
