Rear interior cab floor corner question

[CaptHutch66]

As we have reached an impass I am yet again turning to the experts for sum help! My "interior" rear floor pan at the cab corners (the curved portion of the floor pan which meets the outer cab corner and the rear of the cab) needs a skin graft and I can't seem to locate this "repair/patch" piece on anything I'm looking at! Can anyone help me out and get me pointed in the right direction? What its called, who might have it,etc.Thanks, H