Piaget cal9P (1957, top) vs Omega cal540 (1958, bottom) -- quite a self-explanatory picture. Obviously the Omega cal540 is the Piaget cal9P and not without reason as the Piaget-movement was the thinnest for decades since 1957.

We can find this ultra-thin movement in few Omegas of the early 1960s and in the Starwatch (ref14741 "Damier") as well.