You can sometimes find them on the sales section of onthedash. It's worth reading up on them here:
http://www.onthedash.com/watches/reference-1133/
I'm rather partial to the 1133G - a little cheaper and with that lovely brushed dial some manufacturers played with in the late 1960s/early 1970s.
If your friend is after a TAG-Heuer Monaco I can't help, it's all a bit too naff for me. The drivers at the time didn't like the Monaco and McQueen only wore it because it looked different. Why after choosing to copy Jo Siffert's overalls he didn't also copy his watch and wear an Autavia no one will know. There've been loads of them on here over the years though, a few minutes' searching SC could give you a few answers.