EMX81L / Island Jockey:
GNTZ has 16 rows including a row 13, that makes it 80. There is no row 17. There is, however, some equipment installed on the "2" side behind row 16 and with removing that stuff, whatever it is, and some squeezing it might be possible to add another two seats - so possibly you both are correct.
The flight, by the way, was operated with two F/A despite having a LF of 94%.