I don't know if I can agree with that... the only definition of communalism that really applies is (from American Heritage):
1. Belief in or practice of communal ownership, as of goods and property.
2. Strong devotion to the interests of one's own minority or ethnic group rather than those of society as a whole.
The other definitions spoke to actual communes. 
Collectivism is certainly more political in definition, and less social.
1. The principles or system of ownership and control of the means of production and distribution by the people collectively, usually under the supervision of a government. (from American Heritage)
2. the political principle of centralized social and economic control, esp. of all means of production. (from Random House)
3. The doctrine that land and capital should be owned by society collectively or as a whole; communism. --W. G. Summer. (from Websters)
I'm definitely no expert on this stuff, but I did study it in one of my Soc classes.
I could buy an argument that Acts 4 displays BOTH before I could agree to saying that Acts 4 leans more toward collectivism than communalism... but, it's kinda splitting hairs, so....
It's not, but I guess it's pretty close.
I think you missed definition number three.
Collectivism could be applied to groups, as stated:
2. Strong devotion to the interests of one's own minority or ethnic group rather than those of society as a whole.
Any definition, at least from an American dictionary, would look try to equate communism to authoritarianism, which is not the same.
Communism is collective ownership and control of production, government, and land. Although collectivism has additional definitions, when applied to a government, it means the same thing as communism.
With that said, there has never been a collectivist or communist government, for that matter. Those we've called communist were actually socialist or authoritarian.
