Right out of the driveway, huh? Sheesh..
I'm not really sure if this means anything with regard to a bed mat, but I can tell you for certain that a fiberglass camper shell from a '00 Tundra shortbed will fit right on a '97 T100 shortbed.. I occasionally use a shell that came of a '00 Tundra to haul stuff.. Last time, "stuff" was a nubian buck goat.. It beat hauling a trailer..
Only thing I can think that might cause a T100 problems with a Tundra bed mat is that the wheel wells might not be in the same place between the two trucks.. Otherwise, the box dimensions seem to be the same..
Best of luck!