Originally Posted by
spendorman
All the B139s I've been though, and that's about 12, have have the rubber surround, but I believe that earlier ones have had cloth like one of yours, and I have seen pics of rotted early surrounds that might have been foam, though I'm not sure of this.
I read somewhere that Radford used a lighter cone on their two unit systems. I repeated it somewhere, can't remember where! And I don't remember where I got the original info!
It might be possible that both your units are original, if they were made at the changeover time for the surround type.