hasPageLabels

Check if the PDF file has page labels.
hasPageLabels([out, retval] VARIANT_BOOL *hasLabels)
This function returns true if the currently open PDF file has page labels.

Page labels are an optional PDF feature, allowing arbitrary strings (e.g., "i", "ii", "iii") to be associated with page numbers.

VB:
hasLabels = viewer.hasPageLabels()
getPageLabelFromPageNum
getPageNumFromPageLabel