Well, I know for a fact, most of the castles from the ( MSX, NES, PC88, PCE, SMS ) and so forth, usually are replicating whatever Germany or Austrian castle, that Disney world is replicating. If not then it is Disney world. However we have the original castle of the real "Vlad the Impaler" who spent the rest of his life, living in his virtual fortress, as a prison, because outside was the people who fought against him. I mention "Vlad the impaler", because the castle from the N64 game ( which you can see clearly in the beginning, and after or before a boss battle ), is that same exact castle.
In logic sense, because of that, it does not really matter at all. There is nothing special about the Castle, asides it is poltergeist phenomenon. In SOTN, it was shown that Dracula is in the underworld, where the twin of this castle is. Another problem is how the Castle crumbles away, this is probably stolen from various fairy tales or the movie "Krull" ( a lot of things are stolen from Crull, if you have not noticed ). The Castle is probably just apart of him, in a way a turtle is actually part plant, or the goo from "Ghost Busters II".
Honestly I do not really care, all I know the castle will all have the similar levels. I do not think any Castle, has not have the same or similar levels removed.