I can dig thru some of the price guide books, but here is the BEST way.
There are several on line auction sites for guns. Perhaps the largest is Gunbroker.com. You will need to register on their site.
After doing that search the CLOSED auctions for guns like yours. Look at the pictures, compare condition, see what they actually sold FOR. Book price is always 2-3 yrs out of date, and generally low.
PS- I have a 100 in .308. Neat little rifles. Make sure you clean the gas system after shooting. If the piston rusts in place, almost impossible to remove action from stock.