I don't buy that. The dash was not made until the car was released onto the final assembly line. So it was built for each specific car, they did not have a storage pile of them to pull from any many assume.
Certainly not avocating or promoting the idea of a MC dash and it's correct the dash was made for a specific car's requirements such as gauges/no gauges, AC or no AC, gear selection indicator or not, etc. but Chevelles and MCs were built on the same lines.
It was near impossible to install the wrong dash by mistake so forget about that idea, too many other variables to content like wrong electrical connections, etc.
I would think the 'blank' dash assemblies would have been started at the same station be they a black SS or wood grain MC blank. From that blank dash face, option-for-option, aren't the clusters and wiring harnesses the same between the two? I only have one MC build sheet (Van Nuys) and it's a LS3/M40/AC car. Block #65 (IP harness) shows the same BR code that appears on many SS Chevelles.
To get a Monte Carlo dash put into a Chevelle would have required F&SO approval, in other words, a COPO! There have been hints that there are legit cars with them but no one have ever provided the documentation to back it up. If it were so, you would think a few would surface with the doc's.
If one were trying to order one that way, I agree. Wish Rick_Nelson would let us know what he found out about the 350 car and just what on the build sheet 'proves' it's a MC-style dash. Unfortunately we'll never know all the stories of factory problems or what's really happened to these cars over the past 38 years.
Q: Is it possible?
A: Was anything
not possible?
Q: Did it happen with this car?
A: Law of probability says no.
But then I've seen a 70 Malibu purchased at an estate sale with the round gauge pod dash but no gauges; identical to a base SS dash. I always thought to get the round pod dash in a Malibu, one had to order the U14 gauge package.