My '79 CJ-7 also has 93 and not 85 in that part of the VIN. I am certain that mine is a 7. Also, I believe that 76 was the first year for the CJ-7, so if you have a 75, that would seem to exclude you from having a 7. Then again, I imagine that as with many cars, there may have been some 76's roll out of the plant in 75. (some 2004 model year cars have been out for a while already.)
If you don't know the difference between a 7 and a 5, just check the shape of your doors. If they are U shaped, like a newer Wrangler, you have a 7. If the rear-end side is contoured to the wheel well, you have a 5. The 7 is longer than the 5 in this area and has bigger doors as a result.