This is not entirely correct, Raytheon were going for a slightly higher frequency (2.6 IIRC) and the FCC ordered them down (forcing the recall of their trial ovens) because GE wanted to use crystal oscillators (klystrons) in the 1.2GHz range, and they wouldn't need to worry about the awful klystrons harmonics if they could bleed into 2.4.

GE moved to magnetrons shortly afterwards anyway, I expect they hadn't had the radar manufacturing scale that Raytheon did at the end of the war.