Confusing Suffix after my 1999 JM Marlins Serial Number

[mmodelli]

Hello All and thanks for allowing me to join !!

I have a very perplexing question to ask ..
I have just picked up what appears to be an immaculate 1999
336CS from my local dealer that has serial number 0107xxxxA
and have ever in my life seen a suffix on a modern day Marlin
Rifle before and have no idea what it can be ?
Has anyone ever seen this before ?

Thanks !

Mark