While I couln't get that page to open, they are right in a sense. Assuming
that "Ziv", "Bul" etc. are pre-exilic names of months, they probably did
originate in the Canaanite culture, and "Phoenician" is often used as a term
for Canaanite.
We do have another ancient "Hebrew calendar", and that is the Gezer
Inscription, dated paleographically to the tenth centry BCE. It lists 8
"months" (the word it uses is Yerax - "moon") and the agricultural
activities that are done during each. 4 of the 8 are listed as "YRXW" -
taken either as a dual or plural, to make a total of 12. You can read more
here: http://www.kchanson.com/ANCDOCS/westsem/gezer.html
Although often called "an ancient Hebrew" or "Israelite" calendar, there is
nothing in the Gezer Calendar that would prove that it is any more Israelite
that Canaanite. Even the name of the writer, spelled )BY, could be the
Yahwistic ABIYAH, or not.
BTW, for some more on the developement of the Jewish calendar, try: