This seems like a silly question... but here goes...
I've just purchased new blades for my Craftsman 42" mower. The blades
are not at all what I'd call "sharp" - which surprised me. Should new
mower blades be sharpened before they are used? or is this angled edge
(but again, not "sharp") proper for a mower?
If it makes a difference, these are mulching blades.

thanks!