Someone e-mailed me to let me know that he had been at Breuer's (Kehal Adas Yeshurun in Washington Heights) when they lit the Chanukah menorah in the shul and, while they sang Ma'oz Tzur, they skipped the last stanza of the song. In fact, if you look in the classic German prayerbook, Siddur Avodas Yisrael (p. 440) edited by Dr. Seligmann Baer and originally published in 1868, you will see that it omits that stanza and contains the following in the commentary:
In some new prayerbooks there is an additional stanza and this is its content: "Chasof zero'a kodheskha..." However, this stanza is not in any old prayerbook and is not by the author [of this song] but a later addition that seems to be from the Kitzur Shelah in the laws of Chanukah.Since I have the siddur open, let me add some points about how it has the Al Ha-Nissim in the Shemoneh Esreh (pp. 100-101) vocalized:
1. No "vav" in the beginning (i.e. "Al Ha-Nissim" and not "Ve-Al Ha-Nissim")
2. "Ha-Porkan" with a kamatz katan and not "Ha-Purkan"
3. "Ve-Achar Ken" and not "Ve-Achar Kakh"