The inspector should have a sizing box that they slip over the top of the robot. We have used a tape measure though when someone forgot to bring the box to one of the league events.
Yes you must have a flag holder.
Yes you must put your team number on your robot, twice, on opposite sides of the robot. Logo, team name and sponsors are optional.
Please, please, please, do a self inspection of your robot using the official form you can find here.
http://www3.usfirst.org/sites/defaul..._Checklist.pdf
So many of the things I need to have teams fix are very basic, like not having a flag holder, or team number which if you do your self pre-inspection would be found and make it highly likely that you will pass inspection on the first try.