While I trust your expertise, I think the Bulova collector I bought this from (and I the other watch that was posted a while ago that you link to - https://mybulova.com/watches/1977-accutron-calendar-13863 was from his collection) knew what he was doing and over several years of collecting Bulova in there 1990s and 2000 a had got pretty deep into rarities and obscurities. So I believe this to be a unique but properly / factory produced watch rather than a franken. It has the correct insert that the skeleton / Spaceview calendar watches have, it's not just an opened watch. Also, the attention to detail is a manufacturers attention, not just a chancy watch maker - as I say the central plate is the one that only appears on the Spaceview calendar and the unique printed crystal seems correct for the design too - in fact it is different from the all the other standard Spaceview printed crystals, which is another reason I think this is a unique factory piece. I think because you cannot say with 100% certainty means to me that both watches may we have been factory experiments. I just dolt think they are made up. He wouldn't have fallen for such a thing.