[T2] Sunroof question

[c.dreike]

Hi,
I'm installing my sunroof into my 71. When fully closed the back end is 
still about 3/8" low as if it didn't ride all the way up onto the ramps 
to push it into the closed position. It does appear to be on the top of 
the ramps.  Anyone know if there is supposed to be a plastic part on the 
ramps for easy sliding that would cause it push up the last little bit?

Thanks,
Chris