One piece old looking MARKER LIGHTS? what the deal?

[CSTGURU]

I got these fender marker lights in with a bunch of parts i recently picked up.
They look exactly like the 67-72 ones except they are one solid piece rather that the split-in-the-middle style. they have GUIDE 81 on them, so i assume 1981 factory gm parts?
I thought the vans all use the same split ones up to 81 and then went to the "smoothie" style which i am familiar with, but these 81 old school looks have me wondering?

[leftybass209]

Van maybe? I usually pirate the smooth van parkers when I see them, and I seem to remember some vans having these in the boneyard.