Mossberg Model 321
Average $75-$100, depending on model or condition- and you did not tell us that.
See a gunsmith
Mossberg
the Winchester model 100 semi-auto rifle was made between 1961-1975.
your winchester model 100 semi-auto rifle was made by winchester in 1962.
your win model 100 semi-auto rifle was made in 1967.
Your Revelation 100 is a Mossberg 321. Numrich (gun parts corp) is sold out. You might check Havlin Sales- but the cost of a stock is likely to be half of the worth of the rifle- or more. Sorry-
With the serial number that you have supplied;your Winchester model 100 semi-auto rifle was made in the year 1963.
it is made in the 1700's
It may be a bolt action Mossberg model 321-320
If you know who made it, and they are still in business, probably.
Are you asking about the first Gun or Rifle? The first gun was made in 1935 it was part of the 100 series (100, 122, 177) the first rifle was made in 1899 (the St louis)