360 rear underbody.

They are rubber coated from the factory, it be easier and look better using Liquid rubber from West Marine it is really good stuff .I used it on my inter fenders wells and it stops a lot noise from those little rocks that hits the plastic and looks very clean https://www.westmarine.com/buy/west-marine--liquid-rubber-inflatable-boat-repair--P010_301_007_508

 

Definitely not removable I'm afraid, it is welded to the chassis.
As Randy noted above, it is a rubberised underbody coating. I'm not familiar with the product Randy mentions above, but 3M also make a rubberised underbody paint - https://www.3m.com/3M/en_US/company-us/all-3m-products/~/?N=5002385+3293241481+3294857497&rt=rud

 

I found some pics of that stuff from West Marine this stuff bullet proof, it was design for repairing dingy boats and rafts
Image Unavailable, Please Login Image Unavailable, Please Login