X2, and if that is the case most of the springs will need to be replaced if they haven't already been. Obviously if it was in a fire the stocks have been replaced.
One of the forum members here, SixgunStrumpet, has a Registered Magnum with an almost bare metal worn finish. I think it looks pretty cool, personally.
With this 25-2, if it's just finish loss, that's not so bad.
How is the metal condition? Any pitting, buffing, worn off markings, or edge/contour danage?
There's a few spots that look like they have some remnants of bluing (cylinder flutes, bottom of trigger guard, etc.)
Probably exposed to moisture (outdoors or improper storage), then followed by a half-hearted attempt to remove the metal damage that took the bluing with it. Bet there is a lot of fine and not-so-fine pitting everywhere but the internals may still be OK.
Offer $200 and feel good about yourself whether seller accepts or declines. You did all you could to put cash in someone's pocket or you acquired a project.
I've seen some guns that went through a fire, and then a dousing with the fire hoses. They look worse than that. To me, it looks like something was splashed all over it, or a glass of grapefruit juice was spilled on it, or it fell into a tub of blood, anything that will remove blue. Whatever happened, if it wasn't taken apart and cleaned, there is going to be some internal damage. I'd offer $100, and go as high as $150. There is too much unknown. At best, its always going to be a refinished gun.
The original finish is gone. If it's good mechanically, it's a candidate for a proper refinish depending on the markings & edges other damage from whatever was done to it. What would it be worth as a refinished gun subtract cost of refinish, make allowance for surprises and allowance for your trouble of doing so. The remainder is what you should offer. He's not going to like the result.
Just because it is rescue able, doesn't mean you should take a loss on doing so. My M25-2 came with a beautiful high gloss deep blue finish.
I have seen several people's attempts at refinishing using rust&blue remover and a very inexpensive cold blue.
It looks to me like someone did a half-arse attempt at rust&bluing removal, or they actually did get the rust and bluing off and then made a half-arse attempt at cold bluing it.
Inexpensive cold bluing will thin rather quickly with handling and cleaning, especially if the metal wasn't prepped correctly to accept the cold bluing...….or if several layers of cold blue weren't put on.
Inexpensive cold bluing has a very distinctive and recognizable smell if you have ever been around it much.
Could be someone tried to remove the finish using Naval Jelly -- maybe it was lightly rusted at some point and they thought to just remove rust? At any rate, that looks mighty like a result of NJ.