First of all did he tell you it was smog legal? Why didn't you have him smog it before you bought it? I see a lot of crawlers for sale that are not smog legal and there really isn't any thing wrong with that as long as the buyer is aware of that. Also a bill of sale doesn't mean much, the dmv only cares about a title and release of liability.
If he told that it smogs then you should get him to smog it, if he told you it won't smog now but will with a new cat then you knew it needed some work to smog. The efi swap isn't a big deal and is actually a bonus, better then a carb and less smog stuff. I wouldn't worry too much yet if you like everything else about the truck. There really isn't very much smog stuff on an Ca 85 22re, charcoal canister, egr, dash pot, pcv and cat of coarse. Does yours have all of that? I also remember reading a thread where a smog tech was talking about efi swaps and said that if the efi was available on your vehicle (it was in 85) and all the parts for your year are installed that it doesn't even have to be reffed.
I'm kinda in your same shoes except mine is an 84 with an efi swap, efi wasn't available on the 4x4 in 84. Even though the guy I bought it from and the guy before him had it smoged I'm aware that I could potentially run into problems smoging it, but I knew that when I bought it. So even if you buy something smoged it doesn't always mean its smog legal. What bothers me more is that I had to find out after buying that the frame was cracked, windshield was loose, radiator leaked and quite a few other things that the po didn't mention. I wouldn't have paid as much if I knew about these issues. I have noticed a lot of sub $6000 crawlers have issues in some way or another it comes down to what your comfortable dealing with.
