I think I may be able to shed more light on my car as it is an 87 930 but from Japan.
I believe Japan has higher emissions restrictions than Europe and so it was probably fitted with a Cat Converter when imported.
I have attached pics to show exhausts.
I know it does not show the cat converter closely but these are the only pics I have currently.
If anyone has documents to confirm that
only the Japanese and maybe USA models had Cat converters as standard, this might answer my question of whether the Euro version does not need one
Many thanks