have 2003 Bonniville did it come with key fob

It may have. Look for the RPO sticker and take a picture of it. Show the picture to the person at the parts counter at your local GM Dealer. The RPO sticker is usually on the underside of the trunk lid, inside of the glovebox door, or on the spare tire cover in the trunk. It will say "do not remove" in big letters and have numbers and letters in groups of three. These are the option codes for your specific vehicle. For example, on my 2000 Grand Prix the keyless entry system was part of option package 1SB. If your Bonneville has the keyless entry system don't buy a new fob from the Dealer. I got brand new fobs for my Grand Prix with programming instructions from Ebay. Hope that helps! Jim