In either case, seems to me that Donny is trying to model the sets we actually saw on-screen, so I imagine that what lays behind those three circles is entirely out of the scope of what he's trying to do.
Actually, I plan on making quite a few areas we never saw. It just makes sense to build the sets we are familiar with first, since each area we have seen requires me to make so many assets (chairs, beds, props, computers, textures, materials, etc). It will be much easier after all the canon areas are done to make the new areas with all those assets already made and at my disposal.
Regarding the three circular lights at the saucer's edge being sensors, I'm not against
the idea per se. I just didn't want to be going against any official
facts if I decide to place something other than sensors there. I always wanted to imagine a lounge with a spectacular forward view in that spot, but after thinking about it, that seems a little too unlike TOS and more like TNG.
Plus, should you decide to help Gambit Realm out with their interior (which is awesome in and of itself, by the way), it would be a good idea to know what you want to do with certain areas of the ship.