Wire wheel the doors to see the rest of the design and a name or patent number if anything like that are on it.
First, Papa Bear has one door, 6 inch outlet and was the first stove designed later called the "Bear Series". Double door stoves are of the "Fireplace Series".
All Fisher Stoves will have Fisher on the door except the later TF-88 which was etched into glass.
The draft caps (intakes) are designed like the original caps Bob Fisher's Father Baxter designed and patented. He sold them to other stove makers as well as others copying his. That is the only possible Fisher part on the stove.
The "Sun Door" was the first arched top door designed in Utah, I'd like to see this one buffed with a wire wheel to show the entire design. Could be something that inspired the later "Sun door" ?? A few licensed Fisher builders made changes, or designed their own stoves to avoid paying royalties to the Fishers. Fisher started by only allowing builders to purchase the doors through them. This kept track of royalties owed. It was easy to go to a foundry to have a pattern for your own door made, even using the back of an original Fisher door.
Fisher welded (or was supposed to) the door hinge plates to the front angle iron corners. There was a fabricator on the East Coast that made a "wide body" double door that had to weld the hinge plates like that on the front panel, but it's not the norm. There were also times that a fabricator would run out of Grandpa doors and use a smaller Grandma set requiring the hinge plates to be welded there.
The screen looks like it was made by the same company that made the early ones '76 - '77 for Fisher. The dimensions of the screen look like a Grandma Bear size. The door opening will measure approximately 17 wide X 10 1/2 high if that is the size of Grandma.
The first post of this thread will identify any known Fisher Stove;
https://www.hearth.com/talk/threads/everything-fisher.48309/
I started that thread 9 years ago so people selling them have an idea of what they have. Going by dimensions given of the Fisher models, you can approximate the heating capacity and most information on the Forum can be used for this stove.