You are correct that the Jetco Navigator was early 60s. It was originally F/F, with single channel rudder escapment on the plans. No ailerons on plans, that other builder added them. According to Outerzone it appeared in Flying Models in 63, but plans don't have copywrite date. So not positive on age. I'm staying 3-channel I think.
But, the similar design Berkeley Privateer (F/F) with a 36" WS was '53, and McGovern's Monster (R/C) was '55.