Hi Rick.
The outer felts are easily removed once the door panel itself is off. There is a phillips head screw at each end of the chrome strip on the door's top edge; remove those two screws and the black felt will pop out with a little persuasion (it has several metal clips holding it in, it's obvious once you start).
You can follow this guide, which I used when I rebuilt my window registers.
http://www.corvettemagazine.com/tech-articles/1968-1982-window-regulator-power-rebuild/
As far as the inside felts go, I can't help you there as they came pre-installed on my new door panels.
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"Let them that don't want none have memories of not gettin' any."
- Brother Dave Gardner