is window primer required?

[j72440rallye]

Had to remove the rear glass to change the filler panel between the decklid and the rear glass.  I was reading online that some used window primer on the body and glass prior to installing the 5/16" window weld to the frame and installing the glass.  Some didn't do it and it still worked fine.  What have you guys done that has worked/ didn't work and is there anything that I should pay close attention to?
Thanks!
  

[js29no]

scuff the paint if it is shiny, then brush on the windshield primer. the butal tape will adhere better. 

[jimynick]

scuff the paint if it is shiny, then brush on the windshield primer. the butal tape will adhere better.

  Yep, what the man said. 

[j72440rallye]

Great, Thanks for the advice!