You typically can screw them in on a car like that. I have never did a 39 Chevy but on similar cars I have done the channel was screwed in with a very short little flat head screw. When tightened the screw bury's it's self into the channel a little so the head is below the surface and the glass or glass frame doesn't hit it. Same with the whiskers, a small flat headed screw to hold it on. Even the ones in my 65 Buick are held on with screws.
I don't like the idea of glueing it at all, seen it, seen it fall out, seen it get glue on things, don't like it.
Brian