Are the blades the same on the Detailer Li and Hi-Viz trimmer?

No. The Hi-Viz has a new wide T-blade with diamond-like carbon coatings on the top and bottom blades. The profile of the Hi-Viz T-blade is narrower for greater visibility. The Detailer Li comes with Wahl's standard wide T-blade. 

You can find a complete breakdown of the differences between the Wahl Detailer Li and Hi-Viz trimmer here.