Definitely not GTX 670. It was a 3 year old GPU, the seller said in the description. It seems like a weak card as the fan is very small but on the other hand, it has an SLI bridge so it might be a good card too. The seller has taken measure to hide the card name but at 5pounds, it is worth a bid, I guess. Just for fun.
Here is the full site
If you read the title it says Model F393
That number would make it a GeForce 8800GT 512MB
You can also Google F393 Video-cards. Not to mention I own one...lol
I can not say forsure on the memory size so it may not be 512mb and as stated above it could be a 9600GT also.
I think all GT's were 512MB and the GS series had less.