Islamabad doesn't give any AOR.
you apply, get your sponsorship approval and thats the only letter you receive until additional document request or remedial or PPR.
i don't know why people talk about AOR from Islamabad.
when you receive GCMS notes only then it talks about when was the file transferred and gives you the principal applicant's UCI and the paper file # which starts from B.
the file # which starts from F comes in the sponsorship approval letter from Mississauga!
and in the gcms notes the e-file is under the option:
INCOMING
Incoming 1:
comments: Islamabad e-storage
before all the pdf attachments