EASTERN ARMS CO is a "Store Brand Name" used by Sears Roebuck & Co on guns made for them by a major maker in this case, a 101.7 made by the Stevens Arms Company and is the same as their Model 311. Springfield is a name used by Stevens on their less expensive models. The gun are mechanically identical to the higher priced models but are less well finished and have hardwood stocks instead of walnut. A "Store Brand Name" gun will be evaluated at about 15 percent less that the same identical gun with the original makers name on it. I would say that $300 is a fair price if the gun is in as good shape as you say it is but remember a fair price is what the buyer is willing to pay and what the seller is willing to accept.