nipper1
Both the Classic, Executive and the Bigtime are Pulsar P4 types, sharing the same module. One exception: The DOW module was never originally fitted in the Executive as the space required to show the day of week was not available on the Executive, only the Classic and Bigtime.
Be aware though that most modules were fitted according to which reed contact was needed in order to make it work. Not all magnets had the same strength, and the modules were therefore fitted and tested individually for correct functionality inside that one specific case. It could be troublesome making the magnetic reed contact work as intended when switching cases, but it's not impossible...
JHH