Australian Market only 3 pipe LHS Classic stock exhaust muffler.
The RHS ones are numbered SILENCER, UPPER T2208414 and SILENCER, LOWER T2208415
I have no idea why Australian market ones are different as the earlier 3 pipe Rockets all had the cats in the ugly crossover box.
We do not legally have to have cats fitted in Australia but I never heard of any coming without them.
The later 2 pipe Roadsters have the cats in the mufflers themselves with the similar ugly cross over box without any cats.
Both early 3 pipe Standards and Classics as well as later 2 pipe Roadster and Touring models have factory OEM accessory muffler kits for Offroad use only with more open, loud and free-flowing mufflers (cat free for Roadsters) that are not strictly legal on road. They are called TORs (Triumph Off Road) and only have one part number for the kit which is on both Roadster mufflers but I am unsure how the earlier 3 pipe versions are numbered.