In the grand scheme of things it only matters if you want the best handloads you can produce. Chances are you could load them and shoot them and maybe not even notice any difference. Certainly neck sizing would make the first firing more consistent.
I've proven, to my personal satisfaction at least, that it is entirely possible to have a new, unfired, unprimed case that has been altered during shipping and handling that is out of round. I've proven this with a runout gage and also by trying to chamber the case that the gage said was out of round.
For me it doesn't take that long to full length size new brass and it gives me the personal satisfaction that I know it's as good as I can make it until I fireform it to my chamber by the first firing. I understand that the factory new cases have to be sized to work in any chamber but after the first firing they become my little works of art.