Yes, the early machined tone controls are 3/4" diameter. I just measured a few snares from the early 1960s, plus the 3 toms and snare on my 1966 kit. They're all the same.
According to pages 21-22 of Richard Geir's "Dating Guides for Vintage Ludwig Drums," the red felt 'baseball bat' was introduced in 1962. Color of felt was changed to white in 1965, but "there is significant overlap of felt color." In 1968, the larger 1" diameter knob was introduced.
However, the earlier 3/4" diameter knob was used "sporadically...throughout the baseball bat era"....and "the small knob resurfaces in large numbers when the baseball bat was discontinued."
The reasons for this? Supply problems from subcontractors? A pallet or two of NOS 3/4" knobs being found in a warehouse? I'll let the Ludwig experts weigh in on this.
My 'Ludwig Bible' is Mr. Geir's book, which is based on the study of over 6000 vintage Ludwig drums, and input from at least 6 collectors.
Regards, MB