I can confirm the Hooker does not have the notch. My OCD told me to add the notch so I did and it worked fine. A simple Dremmel tool or grinder will get the job done.Whatever axle-back exhaust you go with, just keep in mind there is a locating nut on the mid section pipe, depends on the brand, you have to notch an opening for it, otherwise you will risk exhaust leaking because the pipes are not fully seated.
This is the locating nut I am talking about, see how I notch following a blue line.
Brands I know have this notch built in: AFE, Borla
Brands I know do not have this notch: Dynomax, Hooker, Flowmaster
Other brands I don't know.
It shouldn't be a deciding factor when choosing exhaust brands, but keep in mind (1) ones have it probably underwent more through test (2) ones don't have it, you have to do a little bit of cutting and grinding.