830 Park Ave: ...Guest House?

Might this $8.9 million Park Ave penthouse be one of the first to possess its own guest house? It sort of looks that way.

A quick inspection of the property's floorplan indicates that the only way to get to a significant portion of the apartment is to head outside to the 'west' terrace (because yes, there are also 'east' and 'north' terraces) and then waddle on over to what we have dubbed Park Ave's only guest house. The space not only looks like a guest house, but it also acts like one: the current owners use the space as a gym and a studio. And if it walks like a duck and quacks like a duck...

Granted, either we or the floorplan might be missing something (like a door), but let's hope that's not the case. Make your own analysis with the floorplan after the jump.

830 Park Ave, Corcoran