I've run Futaba recievers and crystals in KO radio with no problems. I have also borrowed out KO crystals to guys who have interferences or other problems, have worked OK for them.
But i rather use KO crystals in KO radios because if something happens, KO or other people can't blaim you for using non-KO stuff, but it will work with Futaba - KO
JMI Motorsport / Red Bull Racing
HB Cyclone TC - Schumacher CAT SX & Cougar SV
Advanced Electronics - Autopartner.se - Sav÷x - NorthTQ