this may be a duplicate..
The anti slip on the Merkava II and IV is actually metal bits blasted into the finish. It is not affixed with paint. Fine sand might be the most realistic finish.
The small bits do hold dust from the operation area providing natural camoflague.
I can provide pictures on request from the Israeli Armored Museum.
Dr. Why, jeybbu@rit.edu Rochester, NY
Attached photo give an idea of scale.