As for Rollbar, as the pictures show, there is no room for doubt with his name being spelled on the vehicle and the Autobot logo on the door. The TB on the license plate (below) is probably a nod to his G1 Throttlebot origins (basically legend class with a pullback motor). The character has since popped up in name only for various Transformers toy lines over the years including as a scout class delivery truck in the Revenge of the Fallen. While a long history as a toy, the character and personality doesn't really exist creating a blank slate for the Bay and company to work with. The rest of the pictures of the character can be found at TFW2005. Anyone know the year, make and model of the car for the cheat sheet?
Last, it seems Transformers 3 production has moved to Trump Tower according to ChicagoBreakingNews.com. At least they were there last night when "from 7 p.m. to 10 p.m., flame effects and smoke will be used on adjacent building rooftops along the Chicago River between Wabash & Columbus. Also, there will be flame effects on boats in the Chicago River and on cars on the Columbus Street Bridge and Wacker Drive." The article did not identify how long they would be using the location.
Update: The article mentioned there would be flame effects and smoke...it turns out it more awesome Bayhem on the Chicago rooftops.