My LHS guy answers this question. I got a Servo Reverser similar to your Tower link but it was only $10 from GWS. Now I can use all 6 of my ST47s, cool.

No, you can't just swap wires around in the connector. The servo pulses must be digitally or logically 'Reversed', and that is what that little wrapped up circuit board (yep, another $1 china special) does.

Probably, it also adds some small delay, but since its just flaps, and just hopping bewteen 2 programmed positions and staying there, it should be fine.