Longines 22AS Breguet hairspring question

The quality of the image on Ranfft is such that it is difficult to compare with the subject watch. Partly because the auto wind mechanism obscures portions of the balance cock. The image appears to include a kind of ”yoke” screwed to the balance cock which surrounds the regulator index which yours doesn’t have. Again, the Ranfft image is such that it is next to impossible to ascertain that the movement actually has a Breguet hairspring. I don’t think it does, actually. As great a resource as the Ranfft archive is, it seems that there are often some inconsistencies in the information provided. It is not uncommon for manufacturers of watches to build several levels of finish in the same calibre of movement.

Yes, I believe that the caliber 22AS can be found with either a flat hairspring or a hairspring with a Breguet overcoil. Looking at the photos below, you can see that the triangular hairspring stud of (1) is farther from the balance wheel pivot than it is on (2). This suggests to me that (1) has a flat hairspring and (2) has a Breguet overcoil. Further below is an illustration (3) from a 1949 Longines service manual that shows the difference more clearly.

(1) Source: https://www.ebay.com/itm/174021373146


(2) Source: https://www.wristlabs.store/product-page/longines-cal-22as-stepcase-automatic-movement

(3) Source: @DirtyDozen12

You are welcome! 😀