There are a lot of slate images from TOS out there, practically all of them from the work-print trims sold by Lincoln Enterprises. So, what about the number which identifies STAR TREK to the studio, the one with episode number after the dash? In The Cage, it was 6149-1. Then WNM was 5149-2. WTF? The Corbomite Maneuever was 6149-3. Mudd's Women was 6149-4. 6149 holds steady in the samples I have until: Catspaw, which is 5149-30. Who Mourns is 5149-33. The Doomsday Machine 5149-35. The Changeling 5149-37 The Apple 5149-38 Mirror Mirror 5149-39 Why did the first digit change back and forth? Shouldn't Desilu have had one number for STAR TREK? Then, around there somewhere, Paramount bought Desilu. I, Mudd (Ep 41) is 60341. Tribbles (Ep 42) is 60342. A Private Little War (Ep 45) is 60345. Patterns of Force (Ep 52) is 60352. This must mean ST was Paramount Television show 603 followed by the episode number. The third season gets a new show number again: Spectre of the Gun is 60043-56. Elaan of Troyius is 60043-57. The Enterprise Incident is 60043-59. And so on, to the end (Turnabout, 60043-79). Has anybody ever heard why 6149 flipped back and forth with 5149? Or why the third season was re-numbered to 60043?