Alan,
You didn't say how you got the rust off.....we usually recommend using fine steelwool and a light gunoil. On the stock, if I recall it originally was a varnished finish. If you try rubbing it down with 0000 steelwool (no sandpaper please) and Murphy's Oil Soap to clean it up. Probably best to remove the stocks first and check to see if there are any cracks around the tang region. This will allow you access to the underside of the barrel as well to check for rust. Does it have checkering? If so, then those areas can be cleaned with the oil soap and nylon brush. If you decide to refinish, I would use a tungoil that you rub in with your fingers. Tape off the checkering tightly, so the finish doesn't get into it. On the buttplate....chances are you can get a hard rubber blank and grind it to fitt the stock or look on ebay or on-line auction sites for a steel original with the Savage Indian logo. Good Luck!
Jim