Keep in mind that nickel plating is very soft. It will abrade off very easily. Avoid abrasives and clean with non-abrasive cleaners.
Nickel was the preferred plating finish because it "throws" well. That is the plating will reach inside. If, for instance, you wanted to plate a soda can. Zinc plating will coat the outside entirely and maybe up to 1" deep on the inside. Nickel will "throw" far further inside and perhaps coat as much as 3" on the inside.
Nickel is bright and decorative. It is soft and its corrosion protection is based on coating integrity (like paint). Unlike paint it is less active on the periodic table than iron, so it you scratch through the finish the iron (steel) will be sacrificed to protect the nickel. In other words it will rust faster than a blued gun at that point. So take care of the finish. But don't use any more steel wool on it, and if you need to clean it up with abrasives use 0000 grade of steel wool (and use the steel wool only once).