PR card hasn't arrived yet, will UCI suffice for PRC?

[AK_canada]

Hi, I landed on 18th May... Card awaited - the processing time says ~57days...

During this waiting period, if my parents were to apply for Tourist visa, it categorically asks the applicants - "do you know any PR, state their PR number" - what should they mention in PR card number?

Does the UCI suffice?

Thanks in advance