**Yes** More generally, $\mu(1,G)=\pm 1$ iff $G$ is cyclic of square-free order (iff $\mathcal{L}(G)$ is boolean). Théorème 3.1. of the paper "Fonction de Möbius d'un groupe fini et anneau de Burnside" (1984) by Kratzer and Thévenaz (available [here][1]) states the following (with $n_0$ the square-free part of $n$): $$\mu(1,G) \in \frac{|G|}{|G:G'|_0} \mathbb{Z}$$ But if $\mu(1,G)=\pm 1$ then $|G|= |G:G'|_0$, and so $G'=1$. It follows that $G$ is abelian with $|G|$ square-free, so $G$ is cyclic of square-free order and $\mathcal{L}(G)$ is boolean. The converse is immediate. [1]: https://infoscience.epfl.ch/record/130417/files/fulltext.pdf