4wd struts will bolt in the same as the 2wd struts. The real question is how much shorter are the 2wd struts vs 4wd and how much will it lower it.

A few members have installed 4wd coilovers on their 2wd trucks. They mount up all the same. Supposedly the 4wd struts are longer but i havent seen a side by side comparison to confirm.

 

I wonder if the springs would just fit on the 4x4 strut

 

The springs will fit on a 4WD strut, but I'm not sure that is where they get the lift from. I may be totally mistaken, but I believe the strut body is longer from the bushing eyelet to the spring seat.

You might be better off contacting a drop shop and inquiring about something like McGaughy's front coil re-locator(pictured below) to maintain factory ride. What are you going to do about the rear though, because you are going to be very tail high with a front only lowering.

 

I have shackles for the rear

 

So I'm in the same boat as you as I'd prefer factory ride with a little life from the saggy 2WD. So the top of the strut would be the same since the spacers are the same for a 2WD and a 4WD as far as I can see and I can't imagine Ford making the bottom bolts any different. Haven't tried it yet, but side by side comparisons look no different except the 4WD having a taller spring