I have the two compression rings and one of them has a "K" or an "R" (Hard to see) stamped on it. What does this mean? Also, do these rings need to be installed right side up, if so, how do you know which side is up?

Thanks

 

The letter-side goes up. No clue what they mean. Don't forget to check the ring gap. .004 per inch of bore. .011-.012 ought to do it.