I wouldn't do a thing until I shot it a bit. It might surprise you. Maybe I'm lucky, but the handful of #1's I've owned were spiffily accurate right out of the gate.
This mirrors my experience with later Ruger #1s, as well as a few of the older ones. I wouldn’t dink around with it until I had shot it enough to know what it does.
I have one of the Boddington series in 300 H&H, and it has been sub MOA right from day one. As to barrel break-in, I don’t buy in. Let the rifle speak to you; if it is acceptably accurate, keep shooting it until groups open a bit, then clean it. Especially with a barrel burner like the .257 Weatherby - the break-in just takes you that much closer to a shot out barrel.
