Hi
To my knowledge there are no simple ways to identify the objects modified by an upgrade.
CDMC Upgrade / Change Impact Analysis could help but will require to have a reference system installed with the target version of the upgrade.
The version for the objects hold in a transport is created when the order is released, thus unlocking the object instead will make you miss versioning for some objects.
Regards
Upgrade / Change Impact Analysis - Custom Development Management Cockpit - SAP Library
Version Management (SAP Library - Changing the SAP Standard (BC))