You are not going to find a test camera exif with 1DsMark IV in it. Test cameras will have a code identifying which of the many versions of test camera it is. The firmware is not going to have a new model number in it until it gets to the production stage.
Canon does not allow testers to post images online, and does not provide raw conversion software, so jpeg images must be used.
Any posting like the one referred to should be extremely suspect.