Bob,
How do these serial #s compare to yours?
45963 serrated ramp sight, highest known # Baby J, has fine knurled early hammer, no ship date known
4989X earliest known # Model of 1953, 4 screw, 2” no ship date known
Yes, on 45963. I found that info on post #25 of "The Really Old Chiefs Special Thread" from 2007.
I show nine "Model of 1953" Chiefs Specials, though, that are earlier than the number you listed.
Here are three blue, 2":
460XX -- shipped September '54
463XX -- shipped June '54
464XX -- shipped June '54
47475 -- nickel, round butt, 4-screw, 2", rosewood presentation grips. Lettered as having "shipped" to H.O. Austin, S&W Sales Manager for "demonstration purposes" on August 30, 1954. This one's mine.
I also list these:
475XX, blue, 3" -- shipped June '54
475XX, blue, 3" -- shipped June '54
483XX, blue, 2" -- shipped July '54
484XX, blue, 2" -- ship date unknown
493XX, blue, 3" -- shipped Jan '55
Hope this fills in a few holes.