So, this is why you should never try and start rumors. Thanks to Skupples over on the owner's thread, detective Skupples strikes.
Currently, there are no non-reference GTX 780Ti pcbs on the market (As far as I know). Also, Nvidia reference PCBs have always used a hole in the little pcb hanging off to the left. The photo from Chiphell shows enough of that pcb extension to know that there isn't one.
However, Detective Kinaesthetic will also strike again:
On closer inspection, the burnt card would actually seem to be a reference HD 7970, or some variation of a reference Tahiti pcb. It is not a reference Pitcairn or Hawaii, as those pcbs are full matte black, with non-visible copper traces. Tahiti, however, isn't a full matte-black pcb, but is thin enough to show most of the copper traces along the card, giving it the appearance of a mostly brown pcb.
Here is a close up of a high res image taken from Expreview (Chinese review website) showing the back of the HD 7970 reference. All components/traces in the burnt picture match that of the HD 7970: