Im not sure and at the moment I dont remember if I seen a cable for the speedometer. That's what distinguish them apart correct one has a cable and the other has a harness. I do remebr I only seen I think 5 wires going to 2 plugs. One probably to backup and other for temp.
ok chevy based engine, is there a year to year I should be looking for. I see alot of 700r4's from the 80's and does or should it have to have come of a 350 or 5.7 ltr motor
If I remember correctly the older 700s had less clutch discs in some, newer will also have all the updates from over the years, unless you can really save some cash, get a newer one.