Pre 64 model 700 in 300 win mag|Winchester Rifles|Forum|Winchester Collector

I inherited a winchester model 70 in 300 winchester magnum. When I type it into try to find the date of manufacture it says 1962. All the information I can find on when 300 Winchester magnum came out says 1963 in the model 70. I do have a story from my grandfather saying that this was a prototype/first edition gun given out to the top 10 best selling retail stores in the US to sell.  Someone bought it before him and then he bought it from them for $200 when they needed money about 30 years ago. I would just like to know if the story is true and if it is some sort of special 300 Win Mag. And maybe if it’s worth anything.

Since I have inherited it I have been using it as my regular hunting rifle. After finding out that it was pre 300 Win Mag production I thought I might not want to be carrying it around hunting any more. Any information on this would be great. Thank you.