If you sent the email, then probably not,
If you recieved it and have something like CSF mailscanner, then possibly yes., in fact doesn't greylisting give you a mailbox where you can release it. ???
However I did discover a fundamental flaw with Greylisting and would personally advise against using it.
Some larger corporates will use a number of email servers all on different IP's.
They send you an email from IP No1. You Greylist this.
The server determines that the email didn't arrive and performs a resend (which is how greylisting works)
But the resend comes from thier email server on IP No2
The server determines that the email didn't arrive and performs a resend (which is how greylisting works)
But the resend comes from thier email server on IP No3
The server determines that the email didn't arrive and performs a resend (which is how greylisting works)
But the resend comes from thier email server on IP No1 ..... again
see where this is going ???. You end up going around in circles.
You may end up where you just never receive the email.
This happened to us, so I had to roll back from greylisting