Probably true.
I did fly for Scandinavian Airline System when we got our first B737 ng's with DAC. (Go google it)

Joined Braaathens shortly afterwords an the CFM 56 on the NG was running just fine, no vibrations, no egt limitations no nothing.

As i understand things SAS was the launch customer for DAC on the B737.

Edit to add: Maybe Bjørn Kjos is caught up in that A - trap :}

The cargo hold carries a very large supply of standard "D" size batteries. Of the carbon-zinc type ha ha!

Why just these two airplanes?
 

"of which two have been delivered so far, with a delay." I wonder if they are beading them up and not telling Boeing. Other 787 operators have had a few faults, but not nearly as many as this carrier. Is there something unique about these two airframes?

Other than they are both leased and not owned by Norwegian, the only other factor is Boeing Gold Care.
They are the only aircraft that Boeing is responsible for in the regards to maintenance.
So Norwegian have more to complain to Boeing about with serviceability, than other airlines.