S1 Vanguards are pretty close to Remington 700 but not quite. The rear needs to be .008" higher on the Vanguard compared to the 700, and the short action Vanguard has different spacing of the front to rear mounts than a 700 short action. A one piece mount for a 700 long action will fit a Vanguard long action though. The .008" difference in the rear mount is something I found on the Talley website. Based on this, I used 700 Talley lightweights on my .243 with a .008" shim under the rear base. Bore sighting it looked close enough, so I took the first shot at 100 yards, bang on. I've also got a 30-06 with a one piece 700 base that I didn't shim, and it required quite a bit of elevation to get on target. I would guess that the S2 Vanguards will be the same as the S1 version for scope mounts.
Kristian