Mudflaps wire in Canvas?

[Harry Moon]

Harry.....what vehicle are the flaps from....?

The ones in the pictures are off of my 20CWT trailer, but they look to be the same as the scraps left on 3 or 4 front fenders of my CMP's. same width, material and folds and stitching at least for the top 2 inches that survived under the metal strip that covered them on the inside of the fender.
I'm assuming it's the common design for mudflaps. Had no remnants on the rear of any CMP I've poked around lately so I can't check.