That's the Winchester Model 490. A very high quality .22 semi-auto with the weight and feel of a Model 100. Built during 1976-1980. Pricey and hard to find.
Impossible to answer without the serial number. Made from 1961-1973.
The Winchester Model 100, the automatic rifle, manufactured by Winchester Repeating Arms Company
400 dollars is very good condition in the most popular calibers. Double that for .284's
http://proofhouse.com/win/index.html
Without the serial number, there is no way to answer the question.