Yes- by the same agencies no less. My son has HFA ASD. They felt originally he did not warrant a diagnosis. However, his behaviors became more pronounced after four.
My sister had a similar situation in reverse. My nephew originally diagnosed with Moderate AD- in later years due to therapy and coping skills would test as Aspergers instead.

Adhd and asd will mask each others symptoms. Many families don't discover the other until the first is adressed. Many other disorders are similar. Here is a strange example of what I'm talking about.

http://www.youtube.com/watch?v=9-ji4NgJsBE&...