SEA-flyer...

I'm not sure if I understand your question correctly. Are you asking whether you can use the RCC upon arrival at NRT?

If that is the case, there is no arrivals service in NRT and the RCC is in the "secure" area, seperate from the arrivals section and you can't go into the secure section unless you have an onward flight that day.

Of course, with appropriate status and/or service class you can access the NRT RCC when you leave for PEK.

(BTW, the "new" RCC has everything that the old one has, plus more. I wouldn't bother with the old one.)