They may accept it. Or an officer may ask you for a new one. That's within the officers discretion so I can't give a definitive yes or no. You can try or you could wait and ask for the extension to submit the new one you said you applied for already. Up to you.
From the IRCC where they say the officer *may ask you for a new one later on*
For any other country, the police certificate must be issued after the last time you stayed there for 6 months or more in a row.
Some countries put expiry dates on their police certificates. If you have a police certificate that expired, include it. We’ll accept it if:
it was issued after the last time you stayed there for 6 months or more in a row
it is not for the country where you currently live
An officer may ask for a new one later on.