Firstly, I would recommend to take advantage of the standard CCLM function(tile) called Decommissioning Cockpit, where a project can be created and unused objects will be listed together with object attributes like object type, last used date, packg...
ST720 08 means SAP Solution Manager 7.20 SP8. According to note 2035999 "These features are available in SAP Solution Manager 7.2", there is no restriction on 7.2 SP level.
From below extraction from note 2035999, your solman version SAP Solution Manager 7.2 SP08 fully supports the function:"SymptomAdditional information and documentation on the following features are required:Automated DVM self-service documents New D...