: Does anyone of you
: know why there is so little information about this watch?
: Was there just a small time period it has been produced or has this
: another reason?

The ad calls it a pre-Carrera, but they were actually contemporaries. The Autavia was also available at the same time. I think part of the reason these watches are relatively obscure is that their more glamorous siblings overshadowed them. Mechanically they're much the same, it's just the plated case and lack of name that meant they could be sold more cheaply and garner less attention now. No reason not to use one as an entry point into vintage Heuer!