Jeff, that's some beat up floor.
In the 3rd pic, look at where the wire is.. that point shouldn't be there.. and off to the left of the pic I see that one of the trans cross support spot welds has pulled through the floor.
The P.O. did happen to say if it was bottomed out on anything, like maybe a stump or had the trans fall out while going down the hwy? It's definitely fixable especially with how solid the floor looks even though it's misshapen.
As for hitting a curb..unibodies do strange things when you bang them up.. I think Fishbreath is on the right track if you hit a curb you may have to go back over the whole car to make sure nothing else is racked if there is no point of impact under the floor where the point is, then it who knows how it was buckled. My 75 got hit in the front (offset head on while making a left) passenger side and it caved in the driver side quarter when it trapezoided the car