^^Thanks, there's a number on the PCC itself, but it has a backslash (/), and they don't accept the number with any special characters. So I will put in the application number instead. As for the validity, I'm going to put 1 year from the date of issue based on this:
http://www.cic.gc.ca/english/resources/tools/perm/express/intake-complete.asp
http://www.cic.gc.ca/english/resources/tools/perm/express/intake-complete.asp
Police certificates are typically valid for one year from the date they are issued.
For the applicant’s current country of residence, the police certificate must be issued no more than six months before submission of the e-APR.