I am sure of the number. what do you think that is off of? I looked at all the later years and none has chrome around the light like this one. All of them were black next to the light???? Go figure...
The cut out looks like they were trying to get more air into the car under their feet. that would not be a good place to pull air into the car as you would get all the heat off the motor. I found header bolts so it may have had a set of tube headers at one time.
There is no stock exaust left anywhere. so he may have ran header mufflers straigh back underneath.
I will spot wield a patch back over it and thank goodness it will not ever show unless you are looking hard for it.