Terminal 2 - China Mobile and/or China Unicom stores open 24 hours?

In Terminal 2 of Beijing Capital Airport is the China Mobile store open 24 hours to buy SIM cards

I will be arriving into Terminal 2 of Beijing Capital Airport at around midnight from the USA, will the China Mobile or China Unicom Stores still be open for me to buy a couple of Cell Phone SIM voice/data pre-paid cards? I saw on the website of the airport that these Telecom stores are in the airport and are opened 24 hours but I wanted to find out from people who have been there-done that to be sure.Thanks