Well, if you are slightly curious then simply open your Revit Project and place the nodes shown in the image below.
The sample shown was tested on some furniture families in a Revit Project and as shown the dining tables were made of meshes! Busted!
Please note that some families such as topo and rpc's always have meshes in them. Also note that the method above will not find meshes that are "not visible" in a family.
Happy mesh hunting!