I should note that there are further variations on the earlier exhausts for Scandinavia and Australia plus it's all a bit vague as can be seen from the fact my parts books have many hand made annotations, so part number probably changed often. Also the numbers stamped on an exhaust may not tally with any of the numbers listed. I have a genuine S2FL2 middle section and the number on it doesn't correspond to any on the microfiche.
I spent quite a while investigating swan neck style rear boxes through my literature collection and although it's not possible to be certain it looks like these were RHD only and fitted to both coupé and spider. The idea that it's a special spider exhaust I guess derives from the style of the rear valance on them but early RHD coupé had them as well, whereas even S1 LHD spiders seem not to have.
