I'd use one or the other, but not both. The problem with the O ring up at the split locks is that valve guide wear will still cause the engine to use a little oil. The seal at the top of the guide does a better job of metering just a tiny bit of oil flow to keep the valve stem from seizing up or wearing the guide out in a hurry.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!