There was some thread where someone mentioned to me that they have what looked identical to the Mac version of the 128 GL, but worked fine in his PC.

As for the NIB card from that interloper seller, unless you are after a Rage 128 Pro in PRO format, I wouldn't buy it. His listing said it was for 128 GL, I bought it (some time ago), and the card was a 128 PRO. I mentioned this to him, but he didn't respond to me. Here's some photos of the contents.

Notice how the card says 128P? I believe the "P" is for "Pro". When I went to setup the drivers, it said it was Rage 128 Pro.