Thanks for your responses, guys. And thanks for moving my post to the appropriate forum -- don't know why I missed that logical place for this topic.
Anyway, as with all things to do with my truck I'd like to see if I can gather enough info to construct the project myself without farming it out to 3rd party.
Referring to your suggestion of '55-'59 radio units, those may be all but impossible to find anymore ..but it is a lead, thanks.
Any more hands-on info is appreciated.