If I had to guess, I'd say 1967. The '67' at the trailing end of the bottle-bottom stamping is likely the bottle's manufacture year. Since distilleries don't warehouse bottles, they are used shortly after arrival onsite. Thus, a bottle made in 1967 was probably filled in 1967.
Old Forester was one of the earliest brands to convert to metric -- I have owned a 1.75L BIB that was bottled in 1977. Thus, at the latest, I'd say you have a mid-70s bottle, but -- for reasons noted earlier -- I believe it's older than that.