I've only had one custom 700 built so I;m no expert, nor am I a gunsmith - but here is what my smith requested when I wanted to build a 280 Ackley. He wanted the oldest 700 action I had. He said something about the seating of the bolt and lugs would be better. We lapped the bolt anyway but I suppose after a 1000 or so rounds, if anything is going to move ever so slightly, if will have already moved.
I wouldn't put a lot of stock into this theory, nevertheless, the rifle turned out well. It is now about a nine pound, blueprinted, safe queen.