anon438
429
63xxxx for the movement is 1972
The case number does not quite fit in 1972?!
Those sample ref 7813 below, with Extract of the Archives, is movement number 628xxx from 1972.
When your movement was finished in 1972, then your watch was finished in 1972 as well.
Maybe your case was pre production or I guess the jump number by number quota for case manufacturers.
Sorry, your 1970 didn't confince me. Show me your Extract from the Archives certificate.