Thanks to all for comments and answers!
I scanned the Portable Apps directory with two other scanners this morning- both scans negative.
I usually let Portable Apps automatically download and update my apps- when I did that yesterday that’s when I got the false positives (I figured they were, but you can’t be too careful).
This evening- I deleted the LibreOffice 4.0 directory on my Portable Apps drive, then re-installed using a .paf file I downloaded directly from the Portable Apps site. I installed the “multilingual” vice “all languages” version- not only did Norton File insight say the .paf was “safe” after the download, but the installation proceeded without any hits.
Mind you, Norton file insight still doesn’t like the two files…but it’s not trying to quarantine them so I’ll be happy with that for the time being.
Perhaps Norton fixed the false positive?