Lol. Don't know what to tell you, but that's how it was done. It makes sense to me instead of stamping two floors, they stamped one and then based on the vehicle build, they cut and added the hump, stich welded it in and added seam sealer.
I'm accepting the answer, just doesn't seem like a good use of time on the assembly line. Seems like back then the number of manuals would be about equal to autos if not more