If this has already been posted I apologize. I am walking out the door and didnt have time to search. Here is proof I believe that they are indeed 2 different characters. Demolishor is white with a red stripe, and Scavenger is Red with a White stripe. Unless ofcourse demolishor changes colors during the movie. They are different characters. Here are some pics.
The scavenger toy looks like the terex400 cause of the shorter treads. But also in the trailer you can see the letters O & K near Dev's head as he sucks in Mudflap. The Demolishor toy looks like it would make bigger wheels like seen in the trailer.