For $13.00, you can order a death record from the State of Missouri. http://health.mo.gov/data/vitalrecords/applications.php
If your local library participates in the Inter Library Loan (ILL) program, you could see if you can order the St. Louis Post-Dispatch for that time period. I know I could do this several years ago but our library no longer participates because of the costs.
It is possible that the person died somewhere other than what the SSDI shows. The SSDI shows where the last check went to from what I understand not necessarily where the person died.
Looks like the newspapers can be ordered from the state Historical Society. http://shsofmo.org/store/research/interlibrary-loan/interlib...