My 64 had no undercoating, and the 63 i have now has no undercoating. There is paint on the bottom, sortof a light blue/grey, but amazingly no real rust at all. But both cars had the think tar rubber coating in the wheel wells, but nothing along the floorboards. Wierd? i never really thought so until now.

The only other car ive had was a 67 and it had a strange undercoating the was put on aftermarket, with the window stickers to prove it, it had the texture of 80 grit sandpaper and came up over the rocker panels.