Sounds likean EG DOM 1956. Should be factory drilled and tapped, it is right around the transition time, easiest way to tell if the drilling and tapping is factory is the Model 99 will be on the side of the receiver ring. At 70% that would not be considered good condition for a collector, but it is fine for hunting. Condition is key to price, but caliber will also push it up. This is one of those caliber's, 358, 243, all get a slight premium. So bottom line, it is really hard to put a price on it not seeing it. What would you pay for a 358 hunting rig, and you should be able to answer your own question. It is not going to be a collector, but will hold it's value and maybe slightly appreciate if taken care of .
Blair