James B,
You have yourself an excellent rifle. The main thing to remember in the .45-70 is that it can only handle trap door loads. I have a 209X45 barrel for mine and love it. I am still awaiting my .45-70 barrel from Ed's T/C. These guns are very nice handling and lightweight. As for stocks, they are not interchangeable. The barrels are. Good for you on your good deal!