No-one seems to have pointed out in this discussion that non-chronometer movements appear to have no unique reference number on them. My own 1959 5512 has the 1530 calibre movement but it is also marked with a unique number 74*** also on the back of the movement. Could I suggest that if you have this second, separate number then you have a chronometer 1530 ( "1530a" ) and if you don't have this then you have a bread-and-butter non-chronometer ( but still excellent ) 1530 calibre.

See the linked image for a picture of my movement ( in a medical journal that would not make you want to look, would it . . . )

Thomas, thanks for your comments on my watch.

Kind regards to all,