I’ve seen a few A2s over here in the U.K. but quite a few have been returned to M16 config. I’ve got a few A2 parts that came with my M3 that must have been salvaged. BAIV also have an A2 for sale that was on a range. Unfortunately it’s seen better days. They’re also restoring an A2 but it’s going back to M16 spec also.
I don’t think anyone will ever find such an original Halftrack as yours Mark, not unless there’s an African Queen II, or a Vietnam Queen or some such long lost untouched example out there.