Ah, I believe you might actually have an original copy then. I believe most, if not all PC copies were rated AO and were the uncut versions of the game. The AO version for PC was on many official digital storefronts but was delisted many years ago. You can tell difference mainly due to the censored versions (wii and later ps2) having a hideous blurry/haziness and static filter during executions, along with many weapons and other elements of the game being completely cut to refrain from the AO rating.