These are a bit of a mine field. They are Chronos made in France for Heuer, and are original. Although the parts are/were widely available on the market a few years ago, so we see quite a few 'put together watches'. The movements weren't signed, so that helped with the process of making up a watch.
With regard to the one you linked to - I would say that the case, hands and dial are genuine Heuer, the outer tachy bezel may be from another Heuer, but it certainly isn't original to this model, I believe it should be blue.

Stewart

: i came a cross this heuer:
:
: http://www.auctiva.com/hostedimages/showimage.aspx?gid=988043&ppid=1122&image=590036507&images=590036507,590036517,590036529,590036539,590036548,590036562,590036571,590036584,590036593,590036609,590036621,590036633,590036647,590036655,590036665,590036678,590036689&formats=0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0&format=0

: can anyone tell me if its a genuine heuer?
: kind regards