"Do you know how to tell an original Rally Pac from a reproduction?
"The clock don't work." That's what you hear at swap meets.
Consider this, they are 48-49 years old. There are two problems with the clocks that happen over time, the bearing points fail (the moving parts, gears or springs pop out) or the points arc over. I got seven 65-67 clocks from a friend who was liquidating a local Mustang Shop's inventory. One had the bearing problem and I couldn't fix it. On the others, I used some small burnishing tools and cleaned up the contacts. The process is somewhat difficult and tedious due to the small size and limited access to the internals. The final operational test was 24 hours on a battery. I adjusted the time advance/retard also. I needed to touch up one. Of the six remaining, five were sold on e-bay, I kept one of the 65-66 types for myself as payment. The point is, it can be done.
Jim