We need to know what the serial number is to confirm the date of manufacture.

Winchester did offer nickel plating, as well as silver and gold plating (on special order) a very small number of Model 1890 rifles. However, I suspect that your rifle was reworked after the fact. Typically, gold plating was ordered on the fancy grade rifles.

If your Model 1890 was manufactured in the year 1905, you can get a factory letter for it from the Cody Firearms Museum records office tell you if it was factory nickel/gold plated.

Bert

[email protected] said
The serial number is 242190. I’m beginning to believe it was re plated by some one. And if it it was, he or she did an extraordinary job. All the numbers and markings are in perfect condition. Wish my grandfather was here to answer some of these questions. 
 
Also, how would I go about getting a letter from Cody fire arms museum?
 
thanks in advance !  

The serial number identifies it as being manufactured in May of 1905 (Ned Schwing’s reference book).  It is within the serial range that can be lettered by the CFM records office – https://centerofthewest.org/explore/firearms/firearms-records/

Bert