Obvious signs of neglect/abuse. Open the action checking for smoothness and no significant resistance in the swing arc as you do so. Take a couple of snap caps and try the trigger. Check the safety, if applicable. When the action is open there will be a spring loaded release, possibly towards the end of the forearm, that will allow you to take off the forearm and after that the the barrels. Taking it down like that will allow you to determine if moisture got it between the stock and metal, if there is no corrosion there chances are it was well taken care of. That looks like a combination of good old fashioned rust bluing and case hardening on the gun. Very few guns are made to that standard today. I have a 1978 Colt Detective Special with fine bluing like that. If there are only a couple of small spots of surface rust carefully rubbing it with a clean old t shirt and Kroil will lift it out and probably render it unnoticeable to a casual glance. If you get it please post pics.