[Cash, Gas & A SS]

My sunroof has chips on the top surface (seemingly from somebody smacking a beer bottle into it). The dealership can order a new glass pane and install for $1200. They center the pane onto the metal slider by eye. I'm concerned that centering the glass by eye will cause the black edging on the pane to be visible from within the car. Even off from by the slightest fraction will be enough to bother me. Its $400 more the sliding assembly - which to me is worth it if it guarantees a like factory sunroof.

If I order both the glass and the slider, will GM or their supplier send the two pieces already attached?