I use two types of marine type HDPE plastic for the hinged part of the panels I make, “grip” plastic for the tailgate lids, and regular texture for the side panels.

They are both marine grade HDPE panels 0.5″ thick.

The grip is used standard on the tailgate lids and is recommend, I can custom build them with the regular plastic if you have a need for it.

Most people prefer the grip when they see it in person, myself included, and I recommended it.

The grip plastic is not an add-on material, it is a different type of plastic, both types are 1/2″ thick,
The two types of plastic are one with a subtle, but still slippery (especially for dogs) texture on it, really just a visual texture.
The other type has a uniform pattern of nubs and the plastic has a grippy (not rough) compound in it as well.
Originally it was for people who had dogs that jumped on the tailgates, in that case the regular plastic was very slippery. After running the grip plastic on my truck for several years I find that it holds up better- the nubs take the brunt of the abuse and don’t show as much wear as the smoother plastic. It has also been surprisingly easy to keep clean, while still providing a stable texture.

My original concern was that the grip stuff would be harder to keep clean, that does not seem to be a problem.
When it comes to durability I think the grip wins out over the regular since scratches occur on the nubs, not right on the surface, but that is just a visual thing.
The regular plastic is very minimal and clean looking with the side panels being an excellent application for it.

Please keep in mind that I am provided with sheets that only have one good side. The back/inside of the panels will have minor scrapes and scuffs from manufacturing and handling.

Here you can see a stainless latch on grip plastic:

And a cam latch on regular plastic: