[jspatz1]

120 lbs robot + 13 lbs battery + 20 lbs bumper = 153 lbs.

Mike is right about the metal trim. There doesn't seem to be be any specs on what that trim must be, so using it to add or manage your weight should be perfectly legal, as long as your bumper assembly remains under 20 lbs. We considered doing it ourselves, but found a place to put the weight within the robot. I think the Q&A response refers to adding "weight" in the form of some ballast piece that is not part of the legal bumper construction.