I can tell you first hand that it's not. Ford contracts Roush for certain services including pre-build, validation, testing, etc. Ask anyone who has worked for them and you'll usually hear the response of "never again". They work their technical employees to the bone and do not compensate them well. Ford does the overwhelmingly vast majority of their R&D in house. Roush exploits their "relationship" with Ford to sell their aftermarket products under the premise that they're Ford approved/warranty compliant. All those Roush Mustangs that they advertise? Everything they've touched is no longer covered under the OEM warranty. And when a failure does occur, they play the blame game and put the customer in the middle, because they don't want to cover anything out of their own pocket.
The Roush supercharger that they sell for the Mustang was developed between Roush and Ford Performance; not Ford OEM. Regardless of which brand the system is labeled under, it comes with it's own separate powertrain warranty, because in the event of a failure, the OEM warranty is null and void. The powertrain warranty is only a 3yr/36K, so once you're past that you're on your own. The OEM 5yr/60K powertrain warranty doesn't apply.