Hey Scott,

The "texture" on the back is called fabric finish or nylon finish. Many materials have a texture based on the conveyor it was processed on.

For example some yellow insulation has a bumpy texture for no other reason that thats the chain conveyor it was processed on.

Rubber can be ordered in "nylon" finish which is a tight diamon pattern finish.

Just an FYI

PS I've investigated the hell outta these trunk matts. I'm gonna do them probably next year. I'll to the correct grey pattern (the current one is inverted), the tan pattern and the speckled pattern.
The E and 71-72 B bodies will never be available in the original "Burtex" material (burlap/hemp based with a painted on pattern). Fords used that material too. There are repro Fords that look like they were (incorrectly) made from burlap material. Those guys like Mopar guys pay $1000+ for the right one or NOS.