Team Durango DESC410R uses a slipperential?

So I was browsing amain hobbies and I come across Team Durango's new short course truck, and I saw it used a combination slipper and center diff and thought hmm.. doesn't mike have a patent on this? It looks to be done a little differently, and I don't know exactly what Mike has a patent for, but it seems very similiar... except it's obviously not as well made. http://www.team-durango.com/race-cars/desc410r/

Thoughts?