However, there are definitive trends in shapes that mark a bottle as very likely to have been used primarily or originally as a container for high alcohol spirits intended for internal consumption, "medicinal" or otherwise.
These examples help point out the vague line that existed between liquor/spirits and medicinal products during the 19th and early 20th centuries.
If a term is unfamiliar, first check the Bottle Glossary page for an explanation or definition.
As an alternative, one can do a search of this website.
There were, of course, various exceptions allowed under the law for "medicinal" products containing alcohol as well as sacramental wines (Okrent 2010).
Although certain elements of the Volstead Act were loosed up (e.g., 3.2% beer was legal to sell again) beginning in April of 1933, repeal of the 18th Amendment came in December of 1933.
(It should be noted that implementation of this requirement began in late 1934, so some bottles made that year will have the noted embossing.) This regulation was repealed in 1964 giving an effective dating tool of 1935 to the mid 1960s for this diagnostic feature (Munsey 1970).