I thought some kids with AS do suffer from separation anxiety? In that they get very upset when their moms leave. Perhaps they are afraid that they won't come back?
Looking back at my son, he cooed at a normal age, smiled at a normal age, sat up around 4 months, crawled at almost 6, walked at almost 11. He even wistled at not even 4 months and would wistle in response to someone else wistling!
One thing he would not do, is make gestures. He would not follow a pointed finger, he would not point at a picture, infact, he did not like looking at pictures. As a baby he also NEEDED a certain pan flute CD played, accepting no substitutes!
I don't think he would have responded to his name, that has always been an issue I remember as a toddler and young boy, you had to call out to him 4-5 times escalating the volume and tone everytime before he would respond. Eventually around 7 I became horrified to realize he would only respond to his name if he was "commanded" like a dog, and even then not all the time. I worked with my family to try and "correct" the problem because it seemed inhuman to do that to him. (We did not know he was AS at the time).
However, I know he did smile, and he did not want to be separted from myself or my mother as a baby. I think it is very hard to go back and reconstruct things, at the end of the day, we are what we are.
One theory I have heard though, is that people with an ASD may have a condition where they don't produce an enzyme or something normally, so over time, damage is done to their nervous system. It depends on how compromised this production is that leads to the onset and severity of the ASD. This would explain why some children seem very normal up to around a year old, even as late as 3 years old, and then something just seems to "happen".