My early 1958 TR3A (TS 27489 LO) came new with black rubber mats. Each was held with two snaps much like a crown about 3/8" diameter just ahead of the carpet that is secured under the seats by the seat tracks - and a third snap of the same type and size up the top of the center of each firewall at the far end of the footwell. When I restored my car from 1987 to 1990, there were no holes for the screws which retain these snaps. And when I finally bought repro black rubber mats in 1991, there where two snaps but the location was different than the originals by about an inch in each case. It was then that I drilled the holes for the round snaps and installed the snaps onto the floor pan to be correct for the repro mats.
I keep the black mats for the TRA and VTR judges. The rubber mats will wear through with the heel of your shoe in about 30,000 to 40,000 miles. So when I bought my new interior in 1990, I ordered two sets of red carpets for the front floors and for the far end of the footwell. I run one pair of these red carpets every day and if I'm showing the car in the village square show, I put in the 2nd set of still brand new red carpets.
Below are my everyday carpets about 3 years ago with about 90,000 miles since they were installed in 1990.
BTW, I've driven "TRusty" more than 2200 miles - already -this summer.