Noticed the 'clutch outer' P/N 23110-HN2-000 has been superseded by 23110-HN2-A00 , and the two clutch washers have been superseded also.
Is there any reason for this like engineering modification due to a problem?
And if I get a new outer clutch, do I need the two newer washers?

Is there a gasket set for replacing the front crankcase cover and oil tank with o-rings and shaft seals?
I've seen an A or B set.

Thanks and Happy New Year