I have a 66 GT coupe, VIN 6R07A203321, with a problem in the upper left corner of the driver's floor pan. Some damage separated the seam between the floor pan and the inside of the rocker panel. The fix appears pretty straight forward except for the piece of rubber that is sticking out from the site where the joint is separated. It appears to be a length of "rubber" with a rectangular cross section that was positioned between the flange of the floor pan and the side of the rocker panel prior to welding. It is hidden from view under the sheet metal except at the point of separation. I've never seen this kind of "hard seal" used between welded panels. It might be that I'm mis-interpereting what I am seeing. Maybe its sealant that was squeezed into a rectangular channel and only looks like a "hard seal".
I've attached a photo that I hope is good enough to see what I'm describing. Has anyone seen something similar.
Thanks,