no they wont be out, the clearances should actually decrease, because the bearing shells will be new.
as long as you get the correct bearing shells its fine.. it will say which bearing shells you need on the old 1s its stamped on it.
bearing shells are quite important to oil pressure, when they wear too much you loose your oil pressure... which is why most people change them while the bearing caps or off, just means its 1 less thing to worry about in the future, and with a better oil pressure less internal wear.
only time you dont change bearing shells is if the crank is all scored up.. but this would be quite a serious problem if bad enough and would require a crank regrind, and the old bearings wouldnt help things.