Yeah, a non-divided military + police usually means a very short and decisive civil war, in observable modern cases. The exceptions tend to involve a divided armed forces, or extensive foreign interference on behalf of the rebels (see: Syria).

For some reason, folks like to cite US foreign intervention failures as proof motivated locals with rifles can beat the US military, but that's not really the right thing to look at, as a bunch of things about those situations are materially different from a civil war (plus there is in every case a ton more to the resistance's armament and materiel than some guys taking their old AKs out of the closet, dusting them off, and digging into their prepper-crates of MREs)