Pony starter clutch plate

I have bought some NOS clutch plates for starter engines.
The set is two plates in a pacage. 2 different plates ??
Does someone know why they are different and, or what is better?
Here some pictures .
Gilbert
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They look more like flywheel clutch brake linings to me.

1A2586 and 4A521 cross and should be the same part, used on 8R 2U 13A 7m, etc. And they are for the starting engine clutch.

Josh and catsilver , Thank you for your replay.
I will fit these both on a D7 4T.
Gilbert