30/30 I assume? Is it the original sight for the gun? You can email Winchester and they should be able to give you more info. You can get the year from their website but pictures in an email could help you with knowing the originality of the parts, which would change the value.
There is a massive range of prices for them due to all the options and the collectible nature of these rifles.
Don't let a few people bring you down on this, they are 120 years and still shooting straight for a reason, they are classic and well built rifles.