On a 525, in version 6.3, my understanding is that you cannot change an access-list per line as you can in 7.0 by line number.
Is it acceptable practice, if you want to add a line in the middle of an access-list to just copy the existing ACL from the config, add the line and paste the new ACL without deleting the existing one?
In other words you are just overwriting the existing ACL rather than deleting, then creating a new ACL with the new line.
Is there any danger in doing this on a production firewall?