Hey Keith,
unfortunately currently there is no way for non-core HANA developers to find out if an inverted index actually is used.
AFAIK it's currently in development to provide this information via the plan visualization.
So for now, the try and check the run time option is all there is.
However, depending on the scenario, e.g. for multi-column-indexes the major benefit of creating the them likely is the implicit creation of concatenated columns as the basis for the inverse indexes.
- Lars