No error message in the OUT parameter table means exactly that, success.
The exact HTTP status code returned by ODATA implementation will depend on the operation: 301 Created for POST, 304 No Content for PUT and DELETE.
Now, if you are looking for a way to log all successfully created entities, than I would create a table just for that purpose and, after the new entity has been created, would wrote the entity's id into that table.
The successful HTTP response includes the primary key (id) of the newly created entity as part of its URI.