I think I have been misunderstood. The entire seat + base can not be swapped from side to side as the seats sit on the bases at an offset to account for the transmission tunnel. The seat itself if unbolted from the metal base can - but this is not what the OP asked about.
Early Discos do not have the seatbelt attached to the seat (at least the 94YM and 95YM I used to own did not), I don't know when this changed as my current 98MY Tdi does not have them attached to the seat either - but my current 2002 Disco does.

