First - tapping a hole for a 5/16 or so hex key plug is very, very, very simple to do - so we’re not talking a huge issue here.
To answer your question - stocks exist that would expose the “said hole” / cleaning port. Google “crazy Ivan” 10/22 stock
you’ll notice that the back end of the stock tang area is low enough that it wouldn’t cover the hole...
So once you mod the gun, you can’t restrict what the next kid might do in terms of swapping the stock out.
Anyway - In my Opinion (and only that) - I’d just make it as safe as the manufacturer designed it so if anyone down the road pushed the limits where it might become an issue, well it wouldn’t be an issue yet still get the nice cleaning functionality out of it - I hate bore snakes as well...
