The CID can be 62154. If UnitID and CID are a 10 digits then people often make the mistake to say that 62154 is only 5 digits. In fact it is "0000062154" in this 10-digit scope.

If you have the correct CID you don't need to fill in the leading zero values in the KG.

I haven't seen any unit that erases the unlock code. All UNL-files should have a multiple of 25 bytes. All characters should be without spaces, line feeds or carriage returns. No extra bytes within the UNL-file. Make sure it's a plain text file without multi-byte unicode.

It’s also always possible to store all applicable unlock codes in the “[X]:\Garmin\gmapsupp.unl” file as a continuous string (25, 50, 75, 100 or 125 bytes or any multiple of 25). Maybe a little bit harder to see the individual 25-char codes and maintain them but it's on the other hand stored in one central place.