That Carrier Model was made by SMA and it was an aftermarket design made for the 03 and 04 model. you could remove the Tow Loops and bolt this one on with the tow loops fitting on top.
I have the same one on my 05 SUT mounted on a R/A rear bumper.
in 2005 Hummer came out with the Factory one that had the tow loops integral as part of each piece. the both mount the same but the SMA model uses the factory topw loops that came with the 2003 and 2004 nodel when the spare tire was mounted inside.
2005 the spare was moved outside, thus the Factory Carrier with Tow loops mounts built in.
I don't know where to find parts for this one, and I just used a 1/2" Locking reciever pin for mine instead of trying to find the Factory Pull pin and it prevents anyone being able to pull the pin only to find out when you drive away that your tire carrier is swinging and banging around unlatched by someone that thinks it was a funny thing to do when it is Not !!
Hope you find the Hinge bracket that you need, if I see any information for replacement parts I will repost.
You may have to try Kijijji or something to find another one and then have spare parts <img src='
http://www.canadianhummerclub.com/forum ... rgreen.gif' class='bbc_emoticon' alt=':mrgreen:' />
GM PART # 15267627 
