Can we put a Noob insert on a VSF sub for shits and giggles?
You can, although it wouldn't make much sense or have any real functional purpose without a GMT hand. There are aftermarket Sub inserts in two colors if you really want that look. I am an insert and dial mix and match fiend and I have discounted both of those notions every time they crossed my mind.
And we still don't know for certain whether the VSF 126610s have the exact same size 38.0mm OD ceramic inserts (and same 29.5mm crystal) that other reps have. I would be very surprised if they don't.
Adding a GMT hand to a model that doesn't normally have one is possible too. But I like to make fantasy creations that at least make sense. Rolex calls the Air King "The Aviator's Watch". A name no watch should have without a GMT hand IMO.