Ownership of a Launched Product

the managed policies

1. AWSServiceCatalogEndUserFullAccess
2. AWSServiceCatalogEndUserReadOnlyAccess
   have this enforcement built in. In the key clause I was after is:
   "Condition": {
   "StringEquals": {
   "servicecatalog:userLevel": "self"
   }
   }
   Easy Peasy!