Notwithstanding the belief that the bottling works closed in 1920, the Owens-Illinois mark on the bottle categorically can’t be prior to 1929 when the Owens and Illinois glass companies merged. Might the bottling works have relocated to a new address in Muscatine after 1920, leading to ambiguity about the word "closed"?
Plant codes are at the left of the Owens-Illinois logo and date codes (as the last digit or digits of the year) to the right. As you’re showing it in the picture it looks like ‘1’ and ‘6’ respectively, but you have it upside down and it's actually ‘9’ and ‘1’. The ‘9’ is for the Streator, Illinois plant in operation from 1930 to present day.
The date code ‘1’ could only be for 1931 or 1941. Although Owens-Illinois decided to move from one-digit to two-digit date codes in 1940 so that a distinction would be made between 1931 and 1941, full implementation was delayed by labour shortages for mould-making in the lead-up to America joining in WWII. As a quick fix, in 1941 they began adding a dot after the single digit but only for soda and beer bottles. Even then, many bottles are missing the distinction.
The dot system was abandoned almost immediately in favour of a full roll-out of two digits (occasionally seen as a small superscript ‘4’ before the single digit) from 1943 onwards.
Although there are various anomalies and exceptions to some of the above I would be pretty sure that’s a 1931 bottle… but you theoretically couldn’t rule out 1941 based on the marks it has.
[One other thing to note, as an aside, is that bottles like this were generally returnable with a typical life up to about 5 years and sometimes as long as ten years. The date of the bottle itself isn’t necessarily the year in which it was last filled].
