You can use most receivers with a KO transmitter (apart from the new 'type-R') with no problems at all. You have to use KO xtals in both TX & RX though if you try futaba xtals in the tx or RX it won't work.

I have used KO, Novak, LRP, Futaba, Jeti and Hi-Tec receivers with a KO transmitter without problems.