The Eaton Posi uses 4 coil springs, the Trac Lock uses the S shaped spring. The Eaton Posi can have 14, 18 or 22 clutch discs depending on which clutch set is used. The GM Trac Lock uses 14 discs if I remember correctly. Ford Trac Lock uses 14, but only 6 have friction material on them.
You have the corporate 8.5 10 bolt. Some had c clip axles and some didn't, but that doesn't make it a BOP or Chevy, they are all corporate 8.5.