Following up on this, Symantec responded with a solution which is to use the pgpnetshare command line, which installs automatically when you install Symantec Encryption Desktop. The manual for it is here: https://support.symantec.com/en_US/article.DOC6312.html
The command to use is
pgpnetshare --verify <path to netshare> --verbose
you can also output the data to a file by tacking on --output-file <pathtofile>
This command lists every file with its path and gives a warning if it's unencrypted. Unfortunately, the output is just an unformatted and undelimited dump so importing into a csv for parsing isnt an option, but you can at least search it with a decent text editor.
Rob