72GT· rust + magic = gold!
I wonder if there were differences in construction? I also welded in 16g sheet metal on both drivers and passenger floors on my 72 GT. The existing floor was fairly easy to rip out due to all the rust, but even unrusted areas seemed thinner than 16g. At one point, I almost scrapped the 16g thinking it was overkill, as 18g would've been easier to shape.