I ask because I've never really read anything by the likes of Anton Pannekoek, Otto Rühle and Herman Gorter, the classical stuff that has mentioned the word 'Libertarian'.
Though in more modern times I don't see any real difference, historically the term libertarian communist has devoloped taking on a more broader views.
No scholar on this, so I'm quoting from articles in the library:
http://libcom.org/library/council-communism
and
http://libcom.org/library/what-council-communism
This puts them in the libertarian camp in my eyes.
Edit: I see you already know what council communism is.
Well, judging by the excerpts I posted, I'd consider it a strategy towards the same goal of communism (which by definition is libertarian since it is classless and stateless), akin to anarcho-syndicalism but working from a different angle.