Adriatic, unless the car was different on the other side, it isn't Pride Lines. Notice four window on the Hiawatha and two on the City of Portland. Don
I get what you're driving at, but My (non-train side of family) Grandma's 36-37 Marx CV had a 1"(?) long divited side, screw base smoke bulb and 2pc forced air shroud, "never made".
Folks and mfgs alike sometimes make one of a kind things that slip out of the door, or made special for folk.
No way to prove it ,doesn't mean it didn't happen. It just means undocumented. And you never know when, where, or if proof rears it head.
Personally, I'd look close at the styles and grade of craftsmanship to make a decision on how long and hard I'd search for info, then buy/sell/price to suit.
Guides, prices etc. are kinda secondary to my (& others) feelings about what's "real" or not anyhow.
I came across the same types of gambles in comic book selling every few years. Being right a few times more than paid for the few times I was wrong about it. In fact , it kinda became a business because of that.
I don't have a lot of experience in buying and selling trains. Most of what I know are childhood memories of Gramps & Great Gramps, TCA night talks, etc etc. (I can recall lots from my days in diapers too. But early onset Alzheimer's may get the best of me. I know mines diminished even in the last 5 years, the next 5 might be ugly and I know it too well)
I don't recall anything about the gate,sorry. Nice match for a lot of other things I recall seeing (like Hellgate and bungalow bases) but that's it.