Classicwatch Vintage Watches

Hello all together.
Can somebody give me some infos on this watch, please.
Is it cal.818 ? How many have been built ? Was it in the sixties ?

Looks like a case reference 1951. I would need the serial number of the movement to date it, but 1960s is a good guess.

# in the bottom is 970709
# mvnt is 1706671

heini

It would date to approx. 1966.