Many liquor bottles and flasks made by Owens-Illinois have a DIFFERENT mold code configuration on the base, as compared to the way the numbers are arranged on most other types of bottles they made. Typically, it is marked with a number called a “Liquor Bottle Permit Number” followed by a dash and a second number which is the date code. many of the liquor flasks made by Owens-Illinois have the “Diamond and Oval with an I” logo embossed sideways on the base of the container.
https://www.glassbottlemarks.com/owens-illinois-glass-company-bottle-container-marks/