It turns out that the original Las Vegas Skyline set, LEGO Architecture 21308 Las Vegas, did make it out of the factory.
Last year, a LEGO Architecture set – 21308 Las Vegas – was pulled from release and replaced by 21047 Las Vegas (review). It was due to the tragic shooting that occurred involving the Mandalay Bay Hotel, which was one of the buildings in the original version.
It was understood that no copies of 21308 were produced, but this has turned out to be incorrect. The Brick Architect website has acquired a copy of the original version from a shop in South Africa, where a small number of sets were sold. This means that at least a small run of the sets were produced.
What is especially surprising is that two elements are in the set in Pearl Gold – part 32125, Technic 3-Blade Rotor and part 32952, 1x2x1? Brick w/ 2 studs 1-side. There cannot have been such a tiny quantity produced just to service two dozen copies of this set, so there is presumably a batch of these bricks stored in a LEGO warehouse somewhere.
The Brick Architect has kindly provided instructions for this edition of the set, so with a bit of colour changing, fans can build involving the Mandalay Bay Hotel and add it to 21074 Las Vegas if they wish to.