You could "ask" at Aspen auto parts in Arizona about the knobs.
http://www.aspenautoaz.com/60-66-chevy-truck-parts.html
On the steering columns there are all kinds of vendors from
Southern Rods to
Ididit themselves for the steering columns.
Look very carefully that anything you buy doesnt come with a super long cancel cam horn contact that is used for column adapters like when they install aftermarket billet steering wheels - Or your horn wont work.