I own multiple 600 and 660 Magnums in both .350 and 6.5 Rem. Mag., from what you are describing there is no way that I would pay even close to$1,000 for that gun!
Pock marks where the rib screws were removed and not filler screws installed, probably filled with epoxy or some other material, cracked stock, old weaver scope that may or may not be good.
You didn't mention if it has the sights on it, the metal floorplate is aftermarket and an upgrade to the nylon floorplate they came with, make sure a dollar bill slides down the barrel channel to the receiver, it should be a free-floating barrel unless someone full length bedded it, also the Magnums have a factory bedded recoil lug and a tang support which the none Magums don't have. NBD if the dollar bill doesn't slide down the barrel channel, that can be easily remedied with a little sanding and sealing which will improve accuracy.
My advice to you is to look around at auctions or a private sale of a 600 ,350 Mag. that is in decent condition, $1200 or less would be a good price and expect to pay $1700 or more from a gun dealer. One more thing to consider, there is "ZERO" collector value to that gun, which is why a most people buy them today, plus they are getting expensive to shoot with ammo costing $100 or more a box!
Another line of thought, a really nice 600 Mohawk is around $800, if you really want that gun for hunting I would think that $550 would be Max. and then just hope that it's accurate!
Like William Suter stated, it's worth what you are willing to pay, just don't pay too much for it, the value isn't really there!