How do I tell the difference (year) between cylider heads?

[Greg Narvas]

I just bought a a used 94 cr125 motor really cheap and the seller gave me a brand new cylinder head to use for the rebuild (motor has a bad crank bearing). How do I tell what year this new cylinder head is from?

On the intake side i see a few stamps...

b - I assume this refers to the a or b type piston

9F168 is one stamp and stamped below that first one is 3UA1J066


Thanks!