It's been mentioned several times in the history of the list, but Crispin explicitly acknowledges Okrand's assistance in the creation of the Klingon words and phrases she used in that novel: [poD]

Why be'joy' doesn't appear in the KGT glossary too is itself something of a question. Perhaps it's a technical or culturally restricted term - maybe one might only find it in Okrand's Unabridged? ;)