Hi Mike,
Some time ago, I was asked to convert some KN2600 files to KN7000 format.
The codes I used in the first 4 Bytes were as follows :

Original KN2600 : $4C $4B $47 $44 - KN7000 : $4A $20 $4B $ 44

As I'm sure you know, these Bytes need to be changed in every component of the 'TFLDxxx' song folder.....(.SEQ .CMP .LSW .PMT etc.)
Quite a big job! However, I found a Hex editor which made the process a bit easier....

I expect that the KN2400 codes will be the same as the KN2600 but I have no way of verifying this.....