As Oliver points out, this is a 2448 D with 20 micron 16K gold plate, rather than the much rarer and more valuable 18K gold 2456.

A number of these have cropped up in Australia over the last six months or so and I'm not really sure what to make of it. I seem to recall one of the sellers saying they had two of these, and the photos in this lot do seem to show two different movements (look at the L in Heuer-Leonidas; in the first two shots, there seems to be a mark below it, in the latter two it's stamped cleanly). I don't know whether a watch isn't selling and is being relisted, or is bouncing between a few sellers, but whichever it is I'm a little wary of these now, however much I like the watch.

As to wearing a gold watch, I don't think age has much to do with it - worn with the right clothes and on the right occasion, I think anyone could carry off a gold watch. Gianvittorio is certainly showing the right way to do it!