NRG Rodeo section access

I am buying 1 last minute ticket for the Rodeo tomorrow night (Jon Pardi, shouldn’t be insanely packed) to join my 2 friends who already have tickets. The plan was just to get a ticket in their section and just find 3 vacant seats in a row.

However, they are in section 638 and the closest single ticket I can find is 640 or 636. So if I just buy any 600 level ticket for access to the upper concourse, will I be able to get into their section? Or do they check tickets at the aisle for each section?

Thanks in advance!