This is kinda old now, but I thought I'd give my opinion. Although I do not have armor, and I won't for a couple years because of money and age, I would like to have the ability to choose FN- if you have a FOTK set of armor. However, as someone brought up earlier, there are possiblyvarious prefixes FOTKs use. For example, the trooper Daniel Craig played had the designation JB-007, for obvious reasons (Not sure if that has been confirmed by Lucasfilm however). If FN is not used as widely as we think, and if other designations like JB- , FO-, and FL-, exist, I think that keeping TK- prefixes would be best, just so there aren't a million prefixes to keep track of, however, if odd designations are rare exceptions, I think you should have the ability to choose or alternate your prefix, if you have the FO armor.