Row 39... that's going to be a VERY tight fit. I believe that the A321neo is not sized the same as the regular A321ceo so we cannot straight up compare to AF. But looking at, for example, Aegean's A321neo.. they only go until row 38 - having "EC seats" for rows 1-7. KLM is planning to one-up that with an extra row through the use of ultra thin seats: Seat map.

While I was applauding the move to the Airbus platform... this doesn't sound good. The extra inch of seat width that the Airbus offers (compared to the 737) we are going to lose in comfort on the legroom.

Edit: Transavia will be having 39 rows. While HV does have row 13, they have no extra legroom seats. So effectively KLM sacrifices row 13 for extra legroom on EB/EC. The rest of the config is identical between KLM and HV. Impression of the HV cabin here. The HV seats seem to be the same Recaro ones as mentioned above.