I always check the headspace on a new rifle. If you don't you are in effect trusting ALL the people how've used or worked on the rifle.. That is a LOT of trust... Otherwise DoubleD was correct. Even military mausers sometimes have mismatching bolts. If the headspace is OK, then there is no problem. Of course the 'collector' value is reduced. On a customized weapon, that value is non-existant.