stock or aftermarket heads?

[1989dangeroustoy]

So I pulled my heads today due to a misfire and a coolant leak, anyway I noticed the head said mahle on it and had a melted heat tab im wondering if these are stock heads or if they have already been replaced once. I Would think they would say Ford on them

 

[buckwill]

mahle makes some aftermarket 4.0 heads with thicker deck surfaces to address crack head problems, i dont know if they have larger valves or not, but from what i have found posted the serious offroad people use mahle when they can