Traditionaly when talking about the skeleton, we refer to the adult skeleton seeing as an adolescent skeleton have more bones that then fuse. I agree that we need to take that into account, but I don’t believe the statement would be referring to an adolescent skeleton.

Pregnant women as well. Now their human body contains two skeletons, thus raising the average number of bones in a human body by a considerable amount. I would guess there’s probably more pregnant women than there are people missing limbs.