No they were placed in the correct inclination (86.4 degrees for all Iridium satellites). Changing the inclination would require too much propulsion. Right now all the satellites would be close together in the same orbital plane -- one following another -- in a lower orbit than final.
The ascending node of satellites in prograde orbit drift westward. Boosting one satellite to a higher orbit also means it will drift slower, i.e., it "slows down" vs. the rest. In this way they can start evenly "spacing out" the satellites around the earth (although they still will be in the same orbital plane).
The next bunch of satellites will be on the same 86.4 degree inclination but on a different orbital plane. By repeating this process they can create a mesh of satellites spaced out in different orbital planes.