Wow, what an incredibly rare car to even exist. I remember seeing one of these in a junkyard - ironically not far from this one back in the mid 80s. And I've seen a Mariner in a yard too about 5 years ago. I've never seen a Westerner, which seems like the neatest one.
On the Briarcliff, the black area is supposed to have a material that 'resembles' tooled leather. Don't know how you would recreate that, at least without a sample in good condition. - Maybe thinned-down spray-on bed liner?
I think the guy at the Rambler Ranch in Colorado has an example of each of them. That'd be a neat sight with them together. Again, just amazing that this exists. I hope someone saves it.