An interesting project! Over 1.000 units were ordered by the German Navy and 600+ were aktually delivered.
Some were build for Germany during the war in "neutral" Sweden!!!! The hull was always the same, but there were quite a few variations in the superstructure and weaponry! I remember that the Graupner ELKE based on a real ELKE fishing boat in the 1950s, also started her carerr as a KFK.
Interesting to note that the other Graupner model, the Whaler RAU XI now on display in the German Maritime Museum at Bremerhaven, was also built for the Navy as an auxiliary sub chaser...similar to the Flower Class Corvettes, which also have a Whaler background...
I would build the new kit as ELKE and the old one convert to a KFK.
Cheers!