Cindy,
The index records in a dbc are not updated when one of its tables is reindexed, it does not need to be. However, when a index structure in a table in a dbc is modified the dbc is update.
My rebuild index procedure deletes the cdx file before rebuilding the indexes. If an index is not included when the indexes are rebuild it is not deleted in the dbc when it's opened. This means that they do not always update automatically, which brings me back to my original question.