Generally I (as an author) ensure that all modules within a dist (which you are calling a "kit" here) have the same version number and that version matches the dist. That way there is no ambiguity. Occasionally this means that more than one "version" of any given module may be identical, except for the version number. I'm happy with that anomaly as the price to pay for consistency.

It is also one of the kwalitee measures so I take that as something to aspire to. Other opinions are valid too, of course.