No, but not far off.
I made a deep fryer out of a gas bottle and gas burner, can put a whole turkey in it, in fact I have.
KFC use broilers, which are like deep fryers but pressurised so the moisture can't escape, and you are talking minimum £3k for a used gas fired one as they are commercial catering equipment, and no I couldn't make one myself lol.
Other than that though, you know they marinate the chicken in milk and potassium chloride, which you can buy (it's like a salt alternative) then make up your spice mix, herbs, spices and monosodium glutamate.