Mark:

If you say it, then it must be true, but I am struggling to think of an instance when Heuer switched from the square / oval / lozenges to the round (waterproof) pushers, without changing the reference number. It sometimes gets a bit blurry with these models from the 1930s through the 1950s, but I thought that when a model went from non-waterproof (snap-back / square or oval pushers) to waterproof (screw-back / round pushers), there was usually a different reference number. It seems that in many instanced Heuer had both the waterproof and non-WP models in the same catalog, with different reference numbers.

What am I missing here?

Thanks,

Jeff

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: Remember that round pushers replaced the non-waterproof lozenges
: without the reference changing on a lot of watches. So can't
: rule out a ref just based on the pushers alone in this period.