Stevens 107B single barrel disassembly

[plateshooter]

I just picked up the above shotgun. When I got it home, the trigger guard just fell apart. It is aluminum, and looks like it crystallized or something and had deteriorated. It appears that the guns internals have to be disassembled to get the screw for the front of the guard out. I have the stock off, but I need to take the gun apart. This thing is under mega spring pressure, and I am hoping someone here has some experience disassembling the internals that they would share. I checked E-gunparts, and they have a replacement trigger guard listed, but if the front screw hole is not threaded, it will cause other issues in replacing it. Any help or direction is appreciated.

Thanks in advance