What I was told long ago in aircooled days is the the workers punching out the rings put a stripe or two so they would know which side--the bottom--to inspect for burrs. 

Jim

On Nov 24, 2012, at 2:07 PM, Tom Lambas <twlambas@GMAIL.COM> wrote:

> I'm wondering why my new metal head gasket rings have two green marks on
> each side; does anybody know?
> 
> Thanks,
> 
> Tom L.