Does the FDR record data about the cockpit door lock system?
While it is not on the required parameters list, it would not surprise me if it would be recorded- most FDRs record considerably more than the 88 mandatory parameters, and cockpit doors are of course interesting in accident investigations.

That being said, it should also come across pretty evidently on the Cockpit Voice Recorder if somebody was trying to get in. The normal request is a pretty distinct buzzer and the emergency request is the same buzzer for 5 minutes unless denied/ cancelled by the pilot. The door also locks quite loudly. Both should be able to be picked up by the general cockpit area microphone (CAM).