The plate is pretty bent up. I'm pretty sure that the bending damage is from someone trying to get the rusted stuck screws/nuts off, unsuccessfully...
It was difficult to get the rusted screw/nut off. The head broke in half so had to use some vise grips and a wrench, with the nut secured in a vise... Took some effort but was able to get the nuts off...
Cleaned the plate and bracket. Next, will get the shape close to being flat then get some of the rust off...