According to the Heuer archives, the non-tachy dial came first.... well I say that because on the dial boards in the Heuer archive that we saw at the LFdC collectors meet, the non-tachy dial is assigned a lower number. See the photo below.

The presence of the tacky dial on the board confirms that it is a bona-fide Heuer dial, if there are any questions around this. I'll post a good story about this later.

I say it is only a "sort of" definitive answer because Heuer's record keeping in those days was haphazard, and although the dial boards are an incredible source of information, I don't think they were compiled with a huge amount of precision with the idea that in 2014, people would be driving to their home on Moonbase Alpha in their flying car (or jet pack) and checking on their phone what a world community of Heuer obsessives thought. Actually they probably expected the flying cars, jet packs, and living on the moon, but they would not have predicted the internet and the OtD community!

Got to go know, more thoughts later. Any views from anyone else?