NOS driver's exhaust pipe 68-70 340

I had a walker pipe that had the same dimple for the tortion bar so I don't believe it's exclusive to factory only. The flat spots that oldkimmer refers to were on the bottom of the pipe. Almost looks like they have bottomed out while driving. I have a pass side NOS factory pipe that's up in the rafters that has these flat spots I'm referring to. Hopefully by the weekend I can get access and post pics. Would like a NOS driver's side to match. Reason for asking and being so specific. Thanks for your time and patience.