Used 737 MAX has no winglets

I recently purchased a few 737-9s from the used aircraft page (on S4B) and they ended up not having winglets! I found this a bit strange since all my other 737-MAX 9 aircraft had winglets when ordered normally. (not to mention that they all do irl) This apparently didn't affect their range, but does affect the fuel flow a little bit. Also, there seems to be no way to add winglets to them after the fact.

attached is a screenshot of one of the aircrafts' details page.