Accidently deleted wpconfig.php

Hello,
I accidentally deleted the wpconfig.php file. There was no way of restoring so I simply uploaded a new wpconfig.php file from the wordpress download. Made sure database and host names and user/passwords were all good.

Site is up and running no proble, but the Auth and salt keys are all gone. Before there were numbers in there.

Do these matter, are they automatically generated on a fresh install?

How do I go about retrieving these numbers again?

Thanks