My apologies for not following your identification protocol, didn't know it existed and do now. Thanks for letting me know.
The Argo GP has the following information on the movement and elsewhere.
Adjusted to 5 five positions
Girard -Perrigeax and Co. swiss
Gyromatic 211974
thirtynine GXM
39
Jewels
Back Case inside: Modele + Depose
Stainless Steel Girard Perregaux 1791 Swiss



I have the exact same watch...
was wondering if the "Argo" logo had any meaning to it? I tried to google it but no luck as yet... Any ideas anyone?
A mate had mentioned that the Argo logo on the watch is identical to a company that produces utility terrain vehicles, which is called "Argo".
Interesting...