Here's how I found my dutchman panel when I removed it.
Looks like the original was cut down the center, and another piece off of a different Challenger was welded over it.
Before I stared grinding down all the bondo years ago that filled the top of it, I swear it was an inch thick.
Funny thing is I never knew for over ten years
I'm sure a lot of us were there at one time though, including myself.
I remember "fixing" the quarter panel on my very first car, (72 Challenger) with screen, cardboard, and bondo
Being 16 back then is my excuse
Live and learn