Int to Int boarding pass at departure gate or at office location prior to departure gate?

I fly on Air Canada from Vancouver (YVR) to Beijing (PEK) arriving on October 11th at 2:10 p.m.
I have a connecting flight on Air China from PEK to Chiang Mai (CNX) later that day at 6:25 p.m.
I will need to obtain a boarding pass for my Air China flight from PEK to Chiang Mai.
My question is whether I can follow the I to I transfer guide explained above and go directly to the Air China departure gate and get a boarding pass when the counter opens, or whether I must check into a transfer office somewhere inbetween to obtain my Air China PEK to Chiang Mai boarding pass? (I'm assuming Air Canada will check my baggage right thru to Chiang Mai from Vancouver) Thanks,