Cabby exhaust

Hi, does anybody know what the difference is between early cabby exhausts (up to 1983) and later cabby (from 1984). Im looking for a new exhaust and have seen that they are listed seperately. Didnt know if the whole systems were different or if parts were interchangeable between them?
Any thoughts?

Thanks
Tom

Slightly different shape.

different at the rear silencer and backbox due to the fuel tank, the hangers are a bit different too. manifold and downpipe are the same fitment though.

not sure about the front silencer?