Referring to the song "Kansas City", is there an actual corner of 12th Street and Vine?

Not any longer!

When the songwriters (Jerry Leiber and Mike Stoller) wrote the song in 1952, they had never even visited Kansas City. There was a corner of 12th and Vine at the time, but it was razed in the 1960s during an urban renewal project. Where it previously stood, a park shaped like a grand piano with a path shaped like a treble clef, and a commemorative plaque, now exists.

Today, the corner of 18th and Vine still exists at the heart of the city's historic jazz district, leading some modern versions of the song to refer to this modern corner instead.

https://en.wikipedia.org/wiki/Kansas_City_(Leiber_and_Stoller_song)
https://www.kcur.org/arts-life/2016-05-16/news-flash-to-the-world-kansas-city-has-no-12th-street-and-vine-heres-why