This was my grandfather's watch. It's been stored since his death in 1959. I do not have the original band, I was told he was wearing it when he died from a long fall so the band may have been damaged then. I could not find a date code inside, but was told he purchased it in the early to mid 1930s. I just put 1931 in the box above since it required a date to complete page. I have had it repaired and back to operating condition, just always curious of exact year of manufacture and model.
Thank you
The date code on the movement is under "unadjusted Swiss"; it's "L8" for 1958. The date code on the case back is under the serial number and is "M3" for 1963. Based on the case date, this watch will be classified as a 1963.
Band is a replacement. Based on style and "China", best guess is 1990's or later.
I find what I think is your grandfather's watch in the 1962 Linebook148.
1963 Sea King "D", with the probability of a replaced movement.
I updated the date for you.