I am not really certain, but it appears as though it could very well be so for several reasons --
It is remarked where Maleficent used to reside.
In the composition of its spires, it appears to be structurally similar to the original (though this case could also be made for the castle in the centre of town).
The circuitry on the walls is similar.
The Lift Stop, Library, Castle Chapel and Grand Hall are not present in the parts of Hollow Bastion accessible from the Postern.
The foundations upon which the castles sit are different.
The waterways are missing from the city part.
The Castle Gates appear to lead nowhere.
I do believe, however, that the castle in the centre of town could be the original after sustaining significant structural damage, or after having both the pipes that dominated the left half of its façade as well as the large heartless emblem.
I would say that the case could be made for either structure being the original, or even for the original being some sort of world akin to Traverse Town that was composed of what remained of the original city and castle, as it appears as though the heartless have already taken the heart of the world, which is ostensibly restored alongside the Destiny Islands, among other places, alongside the vast lands of blue crystal.
This was also my first impression of what the Villains' Vale was intended to be, especially because Diablo and the restored Maleficent appear to operate from it rather than returning to her world of origin.