Is the top tang screw out?
I imagine it is but just asking...
Push the top lever over a bit and slide a long slender but stout punch down into the hole where the top tang screw came out of.
It;ll bottom out in the bolster on the trigger plate that the tang screw threads into, just ahead of where the triggers are attached and pivot on.
That gives you a pretty good and solid place to tap on the punch and by that you are directly pushing the trigger plate downward and off.
Go easy as there is probably plenty of rust and crud built up around the edges of the plate, wood and internal parts.
Easy does it, little by little to avoid breaking wood out from the stock.
The spindle end of the top lever will snap out of the trigger plate and kick to the side under the heavy top lever V spring pressure.
It'll do no good to tap on the bottom of the spindle visible thru the trigger plate as it sets now as the spindle cannot be pushed up and completely free of the frame anyway.
There's more to take apart once the trigger plate is off and the frame is off of the wood, then you can get at the top lever parts and locking bolt, ect.
