From my stamp collecting days and an old catalog, post cards were first authorized by the U.S. Post Office in 1898, and for one cent. That rate persisted until 1952 (when it was raised to two cents).
From what I can tell from the image, it does appear to be early offset or rotogravure printing (not letterpress), which came into vogue late 1920s.
Granted, doesn't narrow the date of the post card down much! :-(
Just a weird way to say I enjoyed the old post card!