It's not unusual that you can't find any info on the Trek 2007 model. They haven't been "officially" released yet. They slowly release a few and then "release" them in the Fall I believe. Happens the same way every year. So don't regard that as unusual, it is perfectly normal.

The thing that is unusual is that your LBS has one and can't tell you about the changes. Simply set the bikes side by side and look. Chances are that the changes are very, very minor.