CB That is a bummer. No experience with hunter stanchions but as I have read Hunter uses an in fiberglass metal plate to attach hardware. The items I have seen all have screws that go from the top into the plate. This does not look to be your case in your photo.
I would start looking for a through bolt or bolts underneath the deck in the area of the stanchion. This my require some headliner removal to see the area beneath the deck where the bolts may be lurking.
My experience with stainless stanchions is that the base can be welded back on to the post. Usually, due to the weld, a stronger connection than the original design. You might examine this as it may save you a few bucks in new metal. Stainless can be polished after the welding and look bright and shiny new.
These things never fail at the end of the sailing season.