Easy - I'm willing to bet the same as you, this stuff screams professional musician. Minneapolis is a big music city and I know of a lot of big-time musicians are from Minnesota. Bob Dylan, Prince, Eddie Cochran and a few others are from bunch of others all hail from here.
I'll ease your mind; it wasn't even close. If they had been there they wouldn't have even made it out onto the floor! Haha!
One of my favs the Jayhawks are also from Minneapolis. Also the Replacements.
Maybe this stuff belonged to Dave Pirner from Soul Asylum? If there was ever a dude I could see rocking this kind of stuff to be cool....it would be him.