Ah, excellent searching, #, thanks for finding that! "Poca" seems to be the primary name -- here's a recording by legendary old time fiddler Clark Kessinger: https://www.youtube.com/watch?v=XGNRhK_cCiA

From there, I've found that the tune is otherwise usually identified as East Tennessee Blues - that's where that nagging feeling of familiarity came from.

Kessinger is definitely the main origin of the Polk/Poca name -- he helped teach and train a lot of the revivalist fiddlers in the 60s/70s. He claims to have learned the song from fiddler Reese Jarvis, of the duo Jarvis & Justice, who recorded the song in 1929. Listen to their recording here -- note that it doesn't feature the "pizzicato" (what I called the 'rough drag/hit section').

TuneArch has an excellent page on the song, but not much else is out there that I can find.