I know the story about those cards. Back in 2012 a big dutch 3dfx collector did an interview on a local hardware website (tweakers.net). Link to actual video is here: https://tweakers.net/video/5965/gathering-of- … deokaarten.html
He was/is? also a member here by the name of Nitrox Infinity. He had over 200 3dfx cards and over 140 were complete in original boxes! He bought them from all over the world, not that many people have bigger collections. (he sold most of them off a couple of years later).
In this video he talks about a fake voodoo3 from china that was rebranded to geforce2mx in the bios and also that even some of them had fake Nvidia geforce2mx brandings on the gpu itself and ''3dfx'' was taken off. At 3.44 minutes in the video he shows the card and it seems to be exactly the same as the one on ebay (minus the sticker ''vga'' on the bios chip).
So I believe the story is not fake and the card is indeed a very rare rebranded voodoo3!
asus tx97-e, 233mmx, voodoo1, s3 virge ,sb16
asus p5a, k6-3+ @ 550mhz, voodoo2 12mb sli, gf2 gts, awe32
asus p3b-f, p3-700, voodoo3 3500TV agp, awe64
asus tusl2-c, p3-S 1,4ghz, voodoo5 5500, live!
asus a7n8x DL, barton cpu, 6800ultra, Voodoo3 pci, audigy1