Queen Atlantic Cookstove - Damper Controls

[Monadnock]

Sorry for probably a dumb question. I've had woodstoves, but never a cook stove and never an old Queen Atlantic. There are two controls around the stovepipe. The first I think is just a slider plate main damper. The second is the little lever which appears to move what I'll call a "flapper" inside. Flapper down is unrestricted flow to the chimney. Flapper up restricts it to some degree. I can't tell if this is supposed to be the oven box smoke/heat diverter?

Anyway, I don't think I'm getting full movement out of the lever and flapper. The lever seems to only move it one way, down/closed. Is it supposed to pop back into the up/open position when I move the lever the other way? It looks like the flapper has sort of weight on it that might serve to open it by gravity.

Any explanations would be much appreciated. Thanks!