A few years ago I bought a Winchester 1873 for quite the sum of money. Its the most expensive gun that I own. I didn't buy it because it was a nice original condition rifle, but more for the fact that it was quite unique. When I bought it, the man said it was fully nickel plated and that it had the Canadian motto painted on the stock. Seems like half that statement is true.
I joined the Winchester collectors forum and posted pictures about the rifle. And many people stated that it wasn't nickel. Some said it was just polished steel, others said silver.
The info that I had was, that the rifle tarnished quite easily. No rust at all just black tarnish when it comes in contact with humidity and sweat.
After doing some research of my own and with help of the members on the site we came up to a solid conclusion:
If It was:
Nickel: It wouldnt tarnish at all, and may get a little dull with age.
Steel: It would rust pretty much instantly with orange surface rust.
Silver: it would tarnish with humidity and sweat...
All this time and I thought it was nickel. Turns out its silver.