Lonnie,
I have posted about this before but here is what I know. The covering was a heavy black paper/cloth like material. Very much like paper money. I have seen remanants and had a couple trucks where most of it was still in place. In those trucks it was held in place with adhesive on the bottom and on the top with the grill itself {47-53 versions} as I recall. On the 54 I owned it was remanants I believe adhesive top/bottom. I have never owned a truck with the original radio in place so I don't know about that. I saved a really nice one for a pattern once and may still have it, I will look around. Back when I was selling parts in 2009-2010 I owned 27 trucks and I found traces/pieces of it in several of them. On some of these trucks it was on the top where it was pinched by the grill itself that it remained, this was always on a truck that you could tell had never been apart in that area.
