Looking at Ks, KRs and early Sportsters, there seem to be three front brake variants used: a half width brake with an alloy brakeplate with a recess for the fork leg, a half hub with a slightly domed brake plate without the recess, and a full hub brake.
My parts books show the brake plates from the back, which makes it hard be sure what goes on what. The brake plate with the recess seems to be the correct one for a KRTT, but I have not been able to figure out whether it goes with the same half width brake hub/drum assembly as the domed version, or whether there are two different half hub drum/hub assemblies, and whether they use the same brake shoes or not.
Also, I have seen what appears to be a conical front hub on some KRTT pictures, before the switch to the full width Italian brakes. Was this a stock item, or a modification?