Rock Guard Gasket on 1964 Overlander

The rock guard in our 64 Overlander is not attached to the body. There's a thin slot above the window frame and a thin slot along the top edge of the rock guard. In each slot there's a long round piece of black plastic/rubber tubing that slides out. It appears the two pieces of tubing may have been connected at one time by a thin sheet of black rubber serving as a hinge. Does that sound familiar to anyone?

If so, is there a replacement part available? If not, how do I attach the top of the rock guard to the body?

Any advice is appreciated!

Laura