Replacement bearings. Theory vs Reality

Now pay attention, because this is complicated (or boring - depending on your interest in these sorts of things)
I am blessed to have a complete spare parts manual (in English) for my Manurhin - and I am indebted my friends in the Manurhin Scooter Interest Group for these invaluable documents, and so armed with these documents I asked PJ Motorcycle Engineers to supply me with the listed bearings and seals.  I was delighted when they said they recognised the part number references, and sure enough they could supply exactly as stated in the spare parts inventory

However, when I got back to my garage and laid out the new bearings to compare with the old ones, something was wrong.  I had the correct new bearings (as indicated by the spares list) but they didn't all match with the actual bearings that I had removed from the engine.  To be clear - the inconsistency is in the crankshaft bearing - flywheel side.
In the exploded diagram to the right, you can see bearings marked as parts No.16 and No.19.
Part No.16 is identified as a 6303 bearing - and indeed the part I removed was a 6303

But my confusion starts with part No.19.
First of all the parts-list shows 2 alternatives for this bearing - depending on the type of coupling your crankshaft has.  This becomes even more complicated as I try to identify the type of coupling - Ive highlighted in blue on the above parts list, the two alternative couplings - and I have no idea what this means (any insight on this would be gratefully received)  All I can confirm is that my own crankshaft has a tri-lobe drive (this could be what the list calls 'polygone') on a 15mm dia shaft - which might lead us to identify with Part No.21 - the 15mm dia oil seal (as opposed to Part No.21A - the 17mm dia oil seal)

I did warn that this is all very complex and boring!
So according to the parts list I should expect to have either a 6303 bearing or a 6203 bearing.  Curiously, the bearing I removed is neither of these

Regardless of what the parts list says,  the actual bearing that I removed from my engine is a 6202. which as can be seen in the photo alongside is very much smaller in diameter than a 6303 or 6203.
(note the 3rd bearing down - the largest diameter one - is the bearing type - 6303 - required for the other side of the crankshaft)

I spent ages scratching my head, checking, cross-checking and measuring and in the end decided that all I could do was simply replace what came out of the engine in spite of what the parts list said.
Fortunately, as I had decided not to replace the transmission bearings (but had bought them anyway), I had a new 6202 bearing (as shown at the top of this photo) so I am all set to get that crankshaft back where it belongs.
I feel slightly anxious.