Can you get a picture from the other side? I can’t tell if it has the adjustable cheek piece or if that line is a hoptic saddle. I thought the A1’s came with the slimmer rail that only had a picatinny on the top, but this gun has a quad picatinny handguard which were on the Gen 1 and Gen 2. That’s not a bad thing, I actually prefer the rail on that gun but the newer one is a little lighter and used plastic rail sections. That looks like a 26” 308 factory barrel, and the 26 Nosler would be a custom. You’ll want to know what else comes with it, a case, torque wrench, .473 boltface bolt, .535 boltface bolt, number of magazines per caliber, etc. Round count on the 26 Nosler is important.
I haven’t been paying too much attention to street prices lately, maybe someone who has bought or sold one recently can comment, but the pricing would depend on what all is included.