I believe the reading depends on the school, but is more common (I read the kanji that way as well). {}{} is a known phrase to mean the "hard part", coming from the last climb on Mt. Fuji () making you breathless (as if you've been struck in the chest, thus ).
I've also seen in my searches, but that doesn't seem all that common. Perhaps one reason it become "munetsuki" in English could be from someone transcribing the technique being unaware of this possible reading (), and therefore defaulted to .