Have the complete dash and glovebox out (but the car didnt have a glovebox in it when I got it) Do you install the new box before putting in the dash? Thanks.

 

You don't have to. The glove box insert is meant to be installed through the front opening, with the glove boox door removed and you might want to go with that approach so you can have easier access to making any wiring, heating/cooling or vacuum line connections after the dash is installed.
Brian