I'm pretty sure Mark Mamuzic doesn't know what he is talking about. He specifically used the word "sleek" in Twitter post. The suit in those pics does not look "sleek". It looks bulky, with the exception of the head. I'm guessing it's one of the earlier iterations of the suit (2.0 or 3.0) before it gets to the more familiar design we've seen in other set pics.
Besides, I'd seriously doubt that Omnicorp they would downgrade his design from what we have been seeing to the design in the above pics. From what I know of the script, they're constantly upgrading and coming out with new and improved versions of Robocop, kind of like the iPod. Going from the familiar design to that would be like going from the latest version of the iPod to the old bulky version.