Am I right in thinking an AN6 fitting uses uses an M14x1.5 thread?

Reason is the handy drain plug someone added to the bottom of my gearbox is leaking and when I investigated the threads have been stripped and the adapter chemical metaled in.

I've sized up an AN6 to AN6 male/male adaptor and it's slightly too big for the hole which is 12mm so I should be able to run a tap straight through it providing M14x1.5 is correct.

Anyone know for sure as my tap set only goes up to M12 so I have to go buy one.