I have to agree with Darren.

We've seen a few of these direct read (or jump hour, or mechanical digital, or any number of other epithets they go by) watches before on the forum before and never been able to conclude that they were genuine Heuers. Albeit the majority were more fake-looking than yours.

This form of direct read watch seem to have flourished briefly in the 70s, probably as a response from mechanical watch/movement manufacturers to the first quartz digital watches that were appearing. Whereas jump hour watches have been around for hundreds of years and still crop up every now and again, even from some of the more prestigious watch manufacturers.

And there's the rub. The direct read watches were often produced by either new manufacturers that seem to have been established for the purpose (Anker, Gigandet, Tenor-Dorly etc) or from established manufacturers with some ownership issues at the time (e.g. Wittnauer, Benrus, Waltham, Gruen). Strangely, all those latter were American-owned even though some of the watches were made in Switzerland. So it seems to have been a response from certain groups of manufacturers to quartz digital, whereas most of the mid- and high-end manufacturers were either ignoring that threat (sometimes to their eventual downfall) or working on quartz analogue watches.

Where Heuer is concerned, we have the period in question (the 70s) pretty well covered with brochures, price lists and other sales information - in fact, I would go as far as to say it is the decade we know most about from those sources, even more than the 80s when Heuer was running into its own issues with ownership, which obfuscates some of the models available at that time. And none of those show a direct read model.

It's not impossible. Few of us, if any, knew anything about the Memphis until Jeff turned one up:

But I'm inclined to agree with Darren again in that this was probably not a Heuer originally. In any case, you can enjoy it for what it is, an interesting curio from the 70s. If you could take some photos of the crown, caseback and ideally the movement and share them with us, it might help form a more definitive picture.