Wilton vise date

[Nitpicker]

Found a new to me old 4" Wilton bullet vise. Brought it home. Inside is the date 6 50. My understanding is that that is the date of manufacture. New information sent to me is that before 1960 the date signifies the end date of the warranty. My date would indicate it was made in June 1945, not 1950. Can anyone verify whether that vintage vise date is manufacture or warranty end?