Smallville was never spedified where it was located until Man of Steel.
Not quite true.
I've mentioned twice in this thread that prior to MOS, Smallville was placed in Kansas in at least one of the Chris Reeve Superman movies, and in 1981 (5 years before MOS), it was in Kansas in Maggin's
Miracle Monday novel. I also quoted the passage (just go back a page).
Much earlier than all that, way back in 1977,
Amazing World of DC Comics #14 placed Smallville in Maryland.