Is the movement of my Speedmaster professional manufactured by Omega ?
No it is not , Omega have always used Lemania movements in the Speedmaster professionals , from 1957 to 1968 the Lemania 2310 have been used by Omega , then Omega decided to ak to Lemania to devellop a simplier and improved version of this movement : the Lemania 1873 look to the movement section on this website here