Only the orientation of the saddles is critical. If the bridge was reversed, the slots for the strings are wrong as well. On these older basses, the slots were simple V shaped, and are not as finicky as the new slots which are filed to the same gauge as the corresponding string. The slots are also angled toward the tailpiece when positioned correctly, so if the saddle is reversed, you can get sitaring. The other issue is there is no district edge for the string to pass over before leaving the slot, so intonation is difficult.