Whats this part? My Turn!!!

Does that end slide off the arm? Im wondering what that stainless sleeve over the aluminum looking arm is there for in picture one. Does that red button do anything? Perhaps the rivet does not penetrate the arm....
It won't come off. It's riveted for sure.
I'm thinking if the rivet is drilled out, it can be used as a bayonet type arm. The only down side is there is no bend in the arm, so when the blades go to park, the blades won't go flush with the bottom of the windshield.
This isn't mine, but I'm trying to help someone out.
He's wanting to use the arms on a B body.