What John said + I would make sure it is a SB2 receiver. If the barrels were fitted at the factory, they should have the last 3 numbers from the serial # of the receiver engraved on the barrel lug that locks in the receiver. If the rifle barrels have them last 3, then you know that the receiver is a SB2. The second letter in the serial# will tell you what year it was manufactured, check the center-fire FAQ's for all years and information.
The set-up is only worth what you are willing to pay, if you want all of the barrels and they are pristine and factory fitted, then I would say it is a good deal. If they are not factory fitted, or the receiver is not a post 1999 SB2, then it isn't worth anything as a combo. The center fire rifle barrels and the muzzleloader barrel w/forend are worth approximately $100/ea, the shotgun barrel around $50, other stock $25-$50 depending if it is a tamer, survivor, ultra varmint. The receiver, if SB2 $75-100, synthetic stocks approx $50.
The big factor in this would be the 3 scopes and rings. If they are cheapies, they add nothing, but if they are quality scopes and rings, then that is where you pick up the value.
Of course if you were to try to build this same combo from 1 $250 center fire rifle you would probably have $750+, then add whatever the scopes and rings cost. Not to mention what could be a nightmare of sending your rifle to the Remington plant in Illion.
