For some reason, the last two posts didn't show up until I submitted mine.
Yes, schools do a lot of marketing. However, the time when you're making the decision is when they are most likely to negotiate. You may want to arrange a meeting, go over concerns to see how they say they would address those concerns, and then write a letter summarizing what was said so you have a record. Like I said before, the biggest thing is to find a school that is flexible. So ask what they do if a child is working ahead in an area, for example. Do they show a willingness to accelerate or differentiate, or do they say, "we have many bright children" or "it's most important for them to learn social skills.?
There is a book by Susan Winebrenner called "Teaching Gifted Studenfs in the Regular Classroom" that may be helpful to get ideas of some of the things that schools may offer.
As far as the actual results, kids do sometimes have profiles like that. I saw an interview once with Nancy Robinson in which she specifically talked about how gifted kids often have very uneven results and how that is very noticeable when testing them. Especially with such a young child, though, it's hard to know if maybe he was less enthusiastic or concentrating less on some sections. The psychologist should be able to help you know if that played a role.