can i put a 03-06 sierra bumper on my 99 sierra ? i think it could fit. and i really like the way it looks but i dont want to get one of it cant fit

 

dont see why not. Dont even know what changed. 99-06 is all the same frame is talking 1500 non HD

 

You can try it and find out.....

Just looking at pictures it seems the 03-06 had angled grill corners that lined up with an angled bumper and 99-02 had rounded grill corners that lined up with a rounded bumper. That doesn't mean the bumper wouldn't necessarily fit but you may want to get a matching 03-06 grill for the lines between the grill and bumper to line up properly.

Only one way to find out.....

 

Lucky for you I still have this pic on my phone from 3 years ago, on a trip I took to AZ

but its reversed from what you are wanting

 

The bumper and grill changed in 03. Everything else on the exterior is basically unchanged.

Bolts right up. Ideally you should use the the matching 03-06 grille with the 03-06 bumper

 

Front frame horns are different aren't they? You can buy the 03+ ones and bolt them on.

 

2002 GMC Sierra Frontend Conversion - Old Dog New Tricks