Left-libertarians of the C4SS variety favor worker control of industry, but the way they (sometimes) frame the issue, I think, plays into the hand of right-libertarians. Consider proposition #55 in C4SS’ Find Your Philosophy Quiz (which I thoroughly enjoyed panning) (emphasis mine):

People who work at a large corporation or non-profit should be entitled to take it over if it is primarily supported by tax dollars or if it is wealthy because of markets skewed in its favor by government-granted privilege.

I can only see this as left libertarianism with right libertarian framing, or else left libertarianism on the defensive; trying to avoid the possibility of being accused of being moochers or something.

Self-described anarcho-capitalists tend to be union-tolerant and sometimes even pro-union to the extent that it’s explicitly understood that we’re talking about private sector unions. Even anti-union ancaps, for the most part, have an attitude of “you’re welcome to try to implement trade unionism (or cooperative economics, or voluntary collectivism, or worker self-management, etc., etc.) on an unsubsidized basis.” Left-libs admittedly go a step further and endorse wildcat strikes and the like, so there are some substantive differences.