As David says, there are a lot of grey areas around these Silverstones (and the version without the name on the dial).

I have seen Heuer day wheels in German, French and Italian as well as English, so the fact it's not in English isn't immediate cause for concern. It is unusual for it to be in white on black though.

The crown is definitely wrong - not only is it signed where we would expect an unsigned crown, it is also a couple of mm too small for the cutout on the case. And I ask myself why an NOS watch would have a replacement crown.

Difficult to tell on the second hands as they are overlaid, but the hour hand, although of the right type, is too narrow compared to the hands we usually see on these.

Production was somewhat chaotic at Heuer in this period, with a number of changes in ownership, so it's hard to be definitive about what did actually come out of the factory. But there are definitely Lemania Silverstones being made from parts (and not always the same parts that were used originally) and some of those try too hard to authenticate the watch with extra signing etc. I think the best advice is to tread carefully, ask questions and be reasonably sceptical.