Thank you for the script, Carolyn; both sets of SQL Statements (the alerts and the notifications) work well on SQL 2012, both on error number and severity level based alerts.

One note to any users is that while the generated scripts do check for any sysalert of the same name, they do not check for any alert on the same condition, which results in an error if the script attempts to put a sysalert of a different name on a condition that a given server already has a differently named alert for.