Before going the Surplus Sales of Nebraska route, I'd give Play Things of the Past a try - they are a LOT less expensive, and he has tons of pots.
Play Things of the Past Pots
He had the pot for an old Philco TV I helped restore. Just be aware that the Clarostat RTV series are huge 2-1/2" round pots. Dual ganged pots they are, but huge.
Anyone have an old Clarostat catalog with their A47 series stuff? Seems they would have made replacements for all the RCA stuff - they covered (gasp!) Muntz! And yes, they made dual element and tapped stuff too.
IRC and CTS also made kits that had various elements, shafts and housings so that custom pots could be "built" - perhaps someone might have one of their old catalogs or an Allied Radio catalog with their potentiometer line listed in it.
What are the orginal RCA part numbers for the pots? Drawing numbers? Maybe RCA superceded them with a new number -they loved doing that!
Cheers,