The filter threads of the lens are 95mm, which is consistent with a 500mm lens. I'd expect that a 600mm lens would need well over 100mm filter threads, since the front objective lens would need to be over 95mm.(600/6.3=95.24) Lenses always need extra diameter for something to hold the lens, and to prevent excessive viginetting. The existing 200-500mm lens uses a 86mm filter, and if this is intended to be a better lens, the diameter needs to increase.
The 95mm filter thread is clearly indicated in the photo, unlike the number 600 which is not clear at all, and could be 500.
I've seen no evidence that the patent being referred to has anything to do with this lens, someone is just assuming.