Or he was a friend of the family, knew how to make small talk, and had discussion about things other than just lenses...

Or Kubrick was a past master at getting the upper hand in his directorial decisions

  Stanley, we really should shoot the Obelisk with this Panaflex

  No, use that one, it was ground out last year by hendrickson in June, when his daughter was doing well in her exams and he always does a better job when his daughter is happy

  (holy fuck how do I argue with that)

So was that anecdote a one-off, or was Kubrick that way with every part of the camera?

Did he visit the summer home of the guy who milled the camera's metal bits? Did he play with the camera assembler's dog?

Lenses are a different class of camera component. The camera itself is just a dark box to advance film, the lens is everything in terms of image quality. The only other component on the same level of importance is the film stock itself.