That is a very good deal. Even if it is beat up a little. So long as the inside of the barrel is good.

Look at the muzzle and make sure there are no nicks, dings, or dents on the crown (the edge where the hole meets the muzzle).

Take out the bolt and look down the barrel and look for any rust, crudd, or pitting. Some crudd (small particles of powder) will likely be normal but beware of extreme ammounts of buildup as this is likely rust. Check the chamber for the same thing.

Take the gun out of the stock and look for rust. Inside the stock usually rusts first if it is neglected.