I think it depends of who made the brass and the specific chamber dimensions. I reformed 1,000 pieces some years ago from military once fired cases. After some measurements were taken I did a neck ream on all cases. I have often heard there is no need with non military brass, but, to be on the safe side I would do some measuring before dumping the powder in with a bullet on top.
I suppose a guy could seat a bullet on an empty case and use some Prussian Blue or other marker on the case neck and see what becomes of it when run in and out of the chamber.