Customer said his E body back seat trunk divider doesnt fit in his Challenger.

I just dug the back seat out of my own 71 Challenger and it fits great. Probably 1/16" gap by the wheel wells. No bind at all even with 1/8" of Dynamat on each side. I even put it in backwards like the customer and even with the driveshaft tunnel cutout in the wrong place it still fits great. I've sold hundreds of these so if there were some oddities they would have popped up by now.

What could it be.........
Someone replaced the wheel wells?
Factory tolerance issue?
Convertible? (I asked - no reply yet)
My car has special narrow wheel wells?