The difference is due to the way that the power mirror attached to the drive motors on the back of the glass.
I have a pair of the power mirror glasses that include the drive pins on the back. They are complete and ready to snap in.
I'll sell the pair for $25 shipped......OBO.
Please send a PM if interested.
[This message has been edited by FieroMeister (edited 11-03-2014).]