Packaging output screen

I would like to package a game with a screen resolution 960x720. No matter what I do the game comes out in full screen.

in a level blue print you can use an execute console command r.setRes HORIZxVERT

(or in this case it would be r.setRes 960x720)
and have that file at the beginning of play

Can one of the ini files in the packaged set the resolution?