It sounds like overall things are moving forward, so congrats on making progress with the evaluations! I am not parenting an Aspie, but have friends who are - and several of the Aspie kids weren't diagnosed until much later - some as late as middle school.
I have also met a parent who was diagnosed with Aspergers as an adult (as well as more than one parent who were diagnosed with ADHD as adults).
With my own two non-NT kiddos, diagnosing their challenges was never a simple one-stop diagnosis, it took several years of observing, evaluating, accommodating, observing, evaluating again etc. We're still learning so much about my ds and he's in middle school. Throwing EG into the mix certainly makes it a bit challenging as well - whether or not your ds is ultimately diagnosed with Aspergers, you'll learn a lot from this neuropsych eval, and you'll go forward and continue to learn more about who he is and how his brain works as the years go by.
Best wishes,
polarbear
