This may (or may not) be helpful:
Here is a link to the 1986-87 SJ410 NT (US) body and chassis section of the Factory Service manual:
http://acksfaq.com/pdfs/86-87sam15-7_end.pdfPage 20.13 has a picture of the chassis and the location of the body mounts.
The isolation rubbers (four in the center mount arms found at the ends of the center diagonal lines in the drawing) for the mounts are round and have a steel cup that rests into the chassis mount point - at least that is what I have experienced with the SJ413 "Sierra". The front and rear mounts comprise of four rubber squares with a hole in them through which the mounting bolts fit. Additionally, I think that there are four more rubber squares that sit at key points between the chassis and the body.
You might be able to obtain detailed information on the exact count and location from an aftermarket vendor on the web who sells replacement body mount spacers. Most of the major North American vendors sell these kits.
I hope that this helps!