Why dont you call up the Call Center and find out for sure? From what I know (which isnt much), if you send the reciept now, most likely they will be unable to match it up with your application.
One of the applicants in June had medicals which were about to expire. Instead of returning her complete application, they only wanted the remedicals. And they also gave her an ID number and assigned an IO, & gave her a deadline before which to resubmit the required documents. That way, she did not have to start all over and waste time. Hopefully the same will happen with you

So, my suggestion would be wait till they get to your file (I know, waiting suckss

), but call them up @ 1-888-242‑2100 (Canadian time 8 a.m. to 4 p.m) and see for sure what they say.
Hope this helps

Good Luck!