Welcome to the forum!

You're right to be at least slightly concerned about that watch though. A number of problems are immediately apparent.

- The Heuer shield in red on a black background. Striking yes, but take a look at the pictures on http://www.onthedash.com/Guide/_Chronographs// Pretty much invariably, when the dial is black or dark grey/blue, the shield is printed in white. I say "pretty much" because it's very occasionally in silver but I've never seen it in red.

- Funky hands. I like the cut off bottom of the seconds hand. But even though Heuer had a lot of models in its range in the 70s, ancillaries like hands tended to be shared across a few models in the range - makes sense, and saves them a bit of money. You won't find hands like this one on any other Heuer from the period.

- "Chronographe Suisse". Heuer might be based in a French-speaking part of Switzerland and have a German-Swiss name but they usually use English spellings on the dial. We'd be looking for "Swiss" or "Swiss made" somewhere on the dial but not as part of a name like this and "Chronograph" is almost always spelled in the English fashion rather than the French.

- That caseback. Heuer is applied somewhat unconvincingly to it but the caseback as a whole also appears to be in rather different condition to the rest of the case. Note also it states "base metal bezel", whereas the case appears to be steel and doesn't have a bezel. Very questionable that the case and caseback belong together. I'd like to see what's behind it too, a movement shot can tell a lot.

- The ad states the watch has no reference. We really would expect one, and a visible serial number. Not having both these in the 70s is very much the exception.

- Those registers. Heuer typically used either round or (rounded) square registers. These "TV"-shaped ones are much more reminiscent of other manufacturers. In fact, the only occasion I can recall Heuer using something approximating this shape is on the Temporada:

and the 741-1, often Champion-branded, chronographs that Jeff has had indicated are original after years of debating them.

That debate perhaps showed that we, much as any watch-collecting community, are not infallible in determining whether a watch is correct. However, we can still work on a balance of evidence and, on the watch you linked, the only immediately familiar Heuer part is the crown. That, and the doubt over the other parts belonging together and lack of parallels with known Heuers would mean I would recommend steering clear.

At that price point, better known Heuers are well within reach. I'd always recommend a first time Heuer buyer stick with a familiar, well-researched and -documented model. We're happy to comment on those too! Good luck with that first buy :)