Yes and no. It's always complicated, isn't it? ggg
The edge of an unretouched flake (especially obsidian) is unbelieveably sharp. The scalpels that Callahan and others used to make were very specialized unretouched flakes.
The stone arrowpoints we use and the great knife that Mystikbow pictured are retouched -- lots of flakes coming off the edge. Consequently, the edge "wanders" around a lot on the micro scale. You need a very straight edge for shaving. But the retouched edges are still very sharp, although they may not feel that way when you handle them.
A bit more info on the obsidian scalpels: a buddy in Oregon, Craig Ratzat, made some for plastic surgeons. The incisions were nearly invisible and the cuts healed more quickly than with steel scalpels. The surgeons quit using them, though, because the obsidian was so sharp that it cut with minimal pressure: they couldn't tell how deep they were cutting! The steel scalpels "pushed back" and they had a better idea of the incision depth. FWIW.