Agreed both lugs need to bear.
I am not saying both lugs will always bear in a new rifle,but we can probably assume a facing cut was made across both locking surfaces in the same setup the bolt body OD was cut.Likely an accurate bench inspection will show both lugs on the same plane.I have seen rough finish on lugs,knocking the high spots off is good.
I think in the mauser the lug recesses are part of a forging process,there may be more opportunity for trouble there.On a tubular reciever like the Rem,I'd expect the recesses have a good chance being machined right .Some heatreat warpage may occur.
I still say it is a real mistake to pull back on the bolt handle to check or lap the lugs.
Put a brass rod down the bore to push on the bolt face if you must,but only apply rotationalforce with the bolt handle.
I suspect you will find the locking lug in line with the root of the bolt handle shows the heavy bearing,but it ain't necessarily true if you are loading the bolt with the handle.