Wouldn't you get the same effect by getting some rust-oleum black paint and re-spraying it?
Bet if you searched Etsy, you find one similar to what you have already
Truck bed liner
Clean the one you have
Or a black one
Scuffed it a bit
Then spray it with truck bed liner
Truck bed liner
Clean the one you have
Or a black one
Scuffed it a bit
Then spray it with truck bed liner