I think I have seen what you are talking about but have never seen the right side if there was any,don't think there was a need for it . The left is to provide duals and guess you were supposed to use the passenger side original for that side pipe. Ones I had said mayby Douglas ? terrible looking design for any flow,think they were for 49-53 as looked like it dumped right against firewall on earlier. Seen them on Ebay time to time for $25.00-$50.00 mayby more ,always wonder if buyers actually install with what is available today. We had a Scotty exhaust repair shop in my home town in the fifties before we ever had Midas and this was what they used to install duals on 49-53 Fords and Mercury,cheap.