Man! You shouldnt mention that you were TWA F\E on 707, coz now im gonna ask tons of lame questions about that bird! Im crazy, ask Lou  :D

About Nav1\2 ID - i had that funny glitch only once. i just tunned it off (or to other beacon), click switches several times, and tunned it back again. It fixed itself. Had this last week inflight KJFK-KLAX. It looks like some FSX glitch.

I believe that was caused by SquawkBox or FSPassengersX running.

Anyway, if up mentioned solution not works for you, you can try to run 707 installer again, and then select REPAIR mode ;)