I took one out with vice grips and the twisting force cracked the epoxy looking filler, revealing what's underneath. It's the identical T20 Security bolt as the other one. It's possible that Ford did a mix of filled and solid on the one non-visible T20 head, but it seems unlikely they would have changed their method on something like that.
I'm baffled as to why they filled one in the first place. A) Why not just use more readily available phillips head bolts then, and B) who cares if someone removes their MAF? And I guess a sub-thought to 'B' would be, if you really don't want people removing it, there are off-the-shelf solutions like the 5-point Torx Plus bolts that I think Honda uses. I was stumped for a while when I ran across that on a project.