When you walk into their office and go back towards the area where Elon's cubicle is, the same photo of the terraforming transition is blown up on the wall: https://www.flickr.com/photos/44124348109@N01/9848295393

Their company mugs also have a heat sensitive image of Mars that terraforms itself: http://shop.spacex.com/accessories-81/occupy-mars-heat-sensi...

Elon is ::definitely:: already thinking about the colonization phase of the project and has taken steps to highlight it to the company and the public.