I pulled my trunk mat out of the goodies closet. The part number stamped in paint is 85050602A. It doesn't have GM stamped anywhere. There is a pressed stamp in a corner 9293. Shape, size, contours and angles all appear the same as the ebay item, except mine does not have a cut-out for the spare tire boltdown rod. The only other difference I could see was the ebay item seems to have a shadow in the closeup view of the houndstooth pattern, mine has very little of this - but I can find a little when I look at a picture in highdef closeup. Shadows are all to the right of each part in the pattern.
In my opinion this ebay item was made by the same manufacturer, just based on the pictures. I don't know if there's any reproductions being made like this. Still doesn't mean these are NOS.