According to Rock Auto, they are two different part numbers. 3.0L uses an Motorcraft RF10 while the 3.8L uses a RF125. From thier pictures, it looks like they have different shrouds. But that doesnt mean it won't work.
I just stuck a escort gt fan on mine, several people have used them also. The 3.0 taurus fan is thicker then the 3.8 taurus fan so it wont fit in most peoples cars. Unfortunitely the 3.8 fan would not even fit in my car so while browsing I found some people were using the late 1990's early 2000 escort fans I they were used from 1997-2003 when they killed the escort off. They are a 2 speed fan like the Taurus and I found the diamater of the Escort fan was within a 1/2" of the 3.8 Taurus fan. But the biggest difference is the escort fan fit within the 4" of space I had between the radiator and the waterpump without anything hitting. they look like this