Yes, kinda like that guy, but for a 2011. Sorry, I'm not sure what kind of mount is needed for a CB antenna.
Well, you would need to figure out which antenna you want to mount. The mounting base/mounting hole sizes can be different.
If you have not chosen an antenna yet, you should consider a few things….
Mounting an antenna off to the side of the vehicle, especially off to one edge, results in a lopsided ground plane under the antenna. While there are No Ground Plane antennas, the presence of the hood/body under the antenna will still impact the radiation pattern of the antenna. That can result in the antenna being directional, and giving you more coverage in one direction over others. May not be an ideal installation...
Ideally you do want the antenna mounted in the center of the vehicle to make the best use of what ground plane you have.
I did a lot of installs on those era Tahoes, and I can say that doing a permanent mount dead center of the vehicle roof is easy and works really well, especially on CB frequencies. Putting an NMO mount right in the center of the roof and installing something like a Larsen NMO-27 would give you the best performance.
If fender bracket is your only option, then you can still use the Larsen NMO-27, with one of these mounts:
Or a more generic mount:
After using the Larsen NMO-27 for 30 or so years, I can strongly recommend it. It's a professional grade antenna and will easily outlast your vehicle. I've got the same one I've had since about 1990, and it's been a lot of miles off road, tree branch strikes, parking garages, etc. It'll cost a bit more than the hobby/consumer grade antennas, but it will pay for itself in the long run.