In the name of the topic you ask how to check when a rule was disabled, but below you ask about a policy package. Then you ask how to check when it was disabled or when was the last hit. It is a bit difficult to understand what exactly information you need.
I assume that you need to check when a rule was disabled in a policy and by GUI you mean one of SmartConsole applications and not Gaia web-interface.
On R77.30:
SmartDashboard > Right mouse click on the rule > Copy Rule UID
SmartView Tracker > Management tab > Paste UID into filter
On R80.10:
SmartConsole > Security Policies tab > Choose the rule > Check in History tab below
or
SmartConsole > Security Policies tab > Right mouse click on the rule > Copy Rule UID
SmartConsole > Logs & Monitor tab > New tab > Open Audit Log View > Paste UID in search