Did any of the earliest Centennials have an I-frame sized grip like the 'Baby Chief's?

No.

When S&W launched the Centennial in late 1952, the frames were all "Model of 1953" frames (1/8" longer grip frame and larger, oval trigger guard), not Baby J-frames like the Chiefs Specials they were modeled after.

Around that same time S&W also released the Chiefs Special Airweight, which was also built on the Model of 1953 frame. Reportedly there were experimental Airweights made on the Baby J-frame; I've not experienced one.

Again, with the exception of a few prototypes, it took the company till mid-'54 to release the carbon steel Chiefs on the new, Model of 1953 frame.

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Wrangler of stray Chiefs
Bob

My very early 'bug screw' Centennial is on the longer modern J frame length.

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Chris
SWCA #2243 SWHF #292

Thanks guys.