I thought the only reason there was a save pattern function was to enable editing of trigs and p locks (jamming) and then reverting to the saved pattern. Saving pattern does not seem to save a kit-link. (As tested on an empty pattern.)
I just did a little experiment and the kit is only linked to the pattern if there is a trig present.
If there are no trigs the pattern won’t remember the kit.
So if you always save your kits as unique files and always have at least one trig present it should do what you want. I can see this being a downer if you just want to play the keyboard and use pattern switch as kit switch, in this case you would need to plAce a trigless trig (function+trig).