changing light bulb of corroded fog light

I imagine you would install the light just as if there wasn't corrosion ;). But in all seriousness, does there appear to be damage? Are the screws rusted over and you can't get them loose?

Also, are you replacing just the bulb or the entire light?

The more i look at it the more i think the entire light needs to be changed out. I just contacted a salvage yard to see if i can find a "new" light. If i do find a new light I am hoping that it will be as easy as unpluging the one and plugging in the next...Do you know if it is as simple as that??