How much accuracy is dependent on the rifle, the factory barrel, the smith, and how square he gets everything, and how much he knows about re-working factory barrels to increase accuracy (hand-lapping the bore, recrowning, setting the chamber back a couple threads and re-cutting to clean it up and ensure it's square, chasing the threads, re-cutting the lug shoulder to ensure it's also square, etc...).
But as far as the physical action of blueprinting a receiver and bolt, yes, it will increase accuracy and consistency just by squaring up everything and ensuring 100% even contact on all the mating surfaces and lug surfaces.
With factory rifle barrels, it's a crap-shoot if it will shoot better or not...Normally they react in a positive way, and they don't usually shoot worse than they did before the work...Kind of a one-way street. But if you're already at 1MOA with factory loaded ammo, it sounds like you have a good factory barrel that should show signs of improvement from blueprinting...Provided the smith knows what he's doing.
Depending on how much he charges to do this type of work, it might be more beneficial to go ahead and get you a nice Bartlein 5R 1:8 twist 7mm Rem Sendero/Varmint contour barrel blank, and just go ahead and have him chamber and install that while he's got it. Or you could see if he'll cut you a good deal later on when you rebarrel it, since you've already paid him to blueprint everything, all he'll have to do is thread, chamber, headspace, and install the new barrel.
