I'm looking to buy a marlin 1894-S off of the Internet and I was wanting to know the value or a website so I can find the value before I buy the gun. They have it starting out at $450 with no reserve. The SN is 020857**. I found a website that said take the first 2 digits and subtract from 100 so this gun would have been made in 1998. Is this true and if so what would the value of the gun be? Thanx for all your help.