Hi,
Most of the postwar exhaust pipes were bent to the same radius - just the length of the tails varied from model to model. The pipes for the Mk1 and Mk3 machines also had a twist in the bends to suit the wafflebox silencer. Plus series and Dragonfly pipes had a collar at the front end (for the screwed ring on the Pluses, and to retain the copper/asbestos washer on the Dragonfly). The only oddities were the pipes fitted to the Mark 4 Sports machines that took various routes around the pillion footrests.
Regards,
Eddie.