I would say the kits are the same just the different decals.
Both kits base on the Hasegawa No. 09083 ( JT83 ) kit Arado Ar234B-2 'Blitz Bomber' released in 2002.
The first Nachtigall ( Hasegawa No. 09085 - Arado Ar234B-2/N 'Nachtigall' ) was released in 2002 as well but contained new parts for the correct version.
The Hasegawa No.09820 kit ( Arado Ar234B-2/N Nachtigall w/Naxos Radar ) was released in 2008 and is the reissue of the JT85 (no. 09085) kit.
IIRC This was the book I read that in. There is an account from the pilot regarding its final (crash) landing and other details. No pictures unfortunately.