Doubt on engine block

[CSKS97]

Hello, i'm new in here and i have a doubt on a 280sl
on the engine block you can see 2 letters ''A'' and ''B''
the original one is pointing to ''B''
The new one is pointing to ''A'' as you can see in the picture.
Can someone explain me what ''A'' and ''B'' Means???
thanks.

[mbzse]

....someone explain me what ''A'' and ''B'' Means?

Internal codes for the steel foundry at M-B factory

[CSKS97]

so they will be no different at all?

[Naj ✝︎]

What is the engine # stamped on the block?

Could be early vs late

naj

[CSKS97]

the ''B'' one is 130.983 and the ''A'' 130.980 but i've seen 130.983 with the ''A'' letter so i figure it has nothing to do...