Looking at the package scripts, it currently checks for the existence of:
/home/osmc/.hts/tvheadend/accesscontrol/1
And only if this doesn’t exist, does it create one from a template. It will however be doing this test on both new installs and upgrades of the package - that can be changed to only new installs if necessary. (It takes a bit of hacking to achieve this in a postinst script)
See below:
I don’t have any tvheadend compatible hardware unfortunately, so I can’t test tvheadend myself.