Check the intertia weight/sear selector assembly to see if it's working freely.
That's shiny upsidedown triangular shaped part just under the safety button inbetween the tangs in the pics.
The inertia weight is a separate piece that pivots from the back side of the selector and swings backwards under recoil. A small wire torsion springs powers it..
It disengages the selector from the sears during the moment of recoil so the gun doesn't double on you.
**During that time the safety is also inoperable.
If the inertia weight part is stuck in the rearward position any amt and the sears dis=connected from the selector piece,,the safety won't operate.
Here's a look at what the inertia weight/selector assembly part looks like from Numrichs parts list.
Sear Selector / Inertia Weight Assembly | Gun Parts Corp.
Also by looking at the action in the pics,,I'd say the hammers are both down and in the 'rebound' position,,not at full cock.
But I could be wrong,,It's been a very long time since I worked on one. Just seems like a lot of uncompressed spring showing for a full cocked position and a very short hammer fall for the same as I remember it.
The RedLable hammers when fired go full forward to strike the fireing pin(s),,then rebound a short distance off the firing pins and are held there. That appears to me where the hammers are now.
However,, even with the hammers in that position (cocked or uncocked) the R/Label Safety should still be able to be moved betw SAFE & FIRE positions.
Put the bbls and forend back on the gun w/o the stock and work the action open and shut. You'll see the hammers retract/cock and can observe if they are being rotated much farther to the rear and then rotate forward again as the gun is closed. That will tell you the sear(s) are not engaging the hammers to hold them at full cock.
You may also be able to see if something is jamming the sears or the selector and then the safety from disengagement.
Just my thoughts and observations/(guesses!) from looking at the pics.