If you can find a hummer dealer they should have the bolts and spacers necessary, or you can order them here for a dollar a piece. I believe there were 2 upper bolts with spacers and 2 in the bottom. They say 10.9 on the head
http://www.gmpartsdirect.com/catalog/frameset.cfm
Please select a corresponding number from the illustration below to view the details of that part.
1) Grille2) Lower grille W/o brush guard3) Lower grille Nut4) Brush guard5) Brush guard BoltDescriptionYearMSRP PriceYour PriceBolt - 2003-07 - 2003-07
03-07 $1.61
$0.96 
