All the windows are tinted on my Excursion. I do believe it helps with the cooling. Mine are not dark, but more than just "A/C Tint"
Also not sure when they started, but most Ford's do seem to have some kind of UV coating on the windows...... I have "Sun Sensor/Transitions" prescription glasses. In my 91 VW, the lenses will darken. In my 3 Fords they will not darken, unless I have the window down, and the sun is coming directly in that window..... They operate off of UV, so that tells me there is some blocking in the glass..... 2 have darker tinted windows, the 00 and the 03, the 07 just has the "A/C Tint" as there is a very slight amount of tint to the glass, it's not a layer ON the glass like the other 2. I know the other 2 are applied tint, as at least 1 window in each vehicle has a defect........ I like the tinted windows 99% of the time (and mine are no where near "attention getters"). The only time I don't like them is at night, trying to back a trailer, I normally put all the windows down so I can see.....
If you like, I can try and get some pictures of all 3, so you can compare.... However, none of mine are "limo tint"........