As far as I know, they were made by Heuer and the OTD reference table is incorrect. It probably came about as they featured on the same catalogue page as the French Heuers.. as you say they are signed 'Swiss' on the dial. Read my write up on them here: http://heuerville.wordpress.com/2010/08/17/heuer-ref-12-chronograph/

The example shown in my photos, I sold for around £1000, maybe a little more, I can't quite remember.. it was in exceptional condition.

Stewart
- Heuerville

: I've become enamored with the Ref.12 and have started to seek one
: out, but I don't know what the current market value is for the
: model. Does anyone have an idea what I should expect to pay for
: one in excellent condition? I'm also curious why the OTD
: reference table lists these in the 'French made' category. The
: pictures I've seen of the watch shows 'Swiss Made' on the dial.

: On a related note, I've seen the Le Jour version and it might be a
: decent alternative. I hear conflicting information as to whether
: or not these were truly made by Heuer. Is current thinking that
: they were in fact Heuer manufactured?

: Thanks in advance!