Hi Stewart, well then I may be wrong - as Dave S correctly says, we have scant hard evidence and mostly rely on polite guesstimates.
I got my position after exchange opinions and - something lengthy - discussions with a few previous owners.
From photographic evidence scattered on the Net and from the very few ones that have come up for sale, the one with half-hour hashes seems the rarer. Still it may well be that the other one is commoner and simply doesn't turn up for sale because owners are so happy with it.
All in all, the numbers must have been so low that even the commoner of the two is always going to be very rare in absolute terms.
Cheers,
Fabrizio