hartly:
Some B737-200 Gravel equiped AC of that vintage had instrument transfer capability. it will be interesting to know the position of that switch and the frequency of nav 1 and nav2.
Interesting point. The 727s I flew of the same vintage had those transfer switches. I understand they were a customer option that my airline ordered. Those switches in the 727 were very rigid and took deliberate action to move. I doubt a crash where the panel survives mostly intact would disturb the crash postion of those switches.