Defroster ducts go behind the radio, so you can remove and replace the radio without disturbing them. I have not seen evidence of duct clips in my '50 and '51. You don't really need them, anyway, as they are sort of crammed in there. You might have extra duct material if you buy new, but trim to length without extra hose/kinking or you won't have enough room for glovebox and radio.
Kent
