You can assign an ACL name or number to an interface even if the ACL does not exist in the switch configuration

In this case, if you subsequently create an ACL with that name or number, the switch automatically applies each ACE as soon as you enter it in the running-config file. Similarly, if you modify an existing ACE in an ACL you already applied to an interface, the switch automatically implements the new ACE as soon as you enter it. (See General ACL operating notes.) The switch allows a maximum of 256 ACLs (IPv4), and determines the total from the number of unique ACL names in the configuration.