On Thursday night, just days before the Bucs’ home opener, two pee-wee youth football teams ran out of the tunnel at Raymond James Stadium and played a scrimmage on an NFL field under the lights.Their pint-sized game was used as a dress rehearsal for the huge new video boards in both end zones of the stadium, which get a grand unveiling Sunday at 4 p.m. as the Bucs host the Los Angeles Rams. “We wanted to do things that had never been done before in a stadium,” said Brian Killingsworth, the team’s chief marketing officer. “We took the approach that if we’re going to do these upgrades, we wanted to be really innovative in the process. It’ll be a unique environment, totally immersive.”