AAR Cuda Gas Cap

Hey guys, I'm building a model AAR cuda and I noticed on the chrome spree there is a tiny flip top fuel cap, I got to searching through the directions and couldn't find it. I looked on google images and looked at the quarter panels and the backsides of hundreds of AAR's and I can't figure out where the hell one would add gas to one of these cars!

Anyone here own a real one that can give me some insight?

EDIT: I can't even find one on a normal cuda, were they behind the license plate or something?