Looks like my speculation was correct the Hunan Handguard is modular
View attachment 120131
"Modular" for a handguard doesn't mean much, and the patent isn't exactly using the word correctly except for saying that the replacement of the existing plastic handguard is done in a sensible way.
Well, it seems like they are keeping the front sight post that has to be physically attached to both the gas block and the handguard, and it looks like the bottom of the handguard has a screw as well, so it doesn't look free floated...
However what's more interesting is that clearly this patent is related to this design we've seen before (below), which clearly doesn't have the gas block front sight post (but uses a front sight post that is attached to the picatinny rail, and this one looks free floated, while also having the overall handguard as a whole be of a similar length to the patent...
I wonder if the patent is of an earlier, less refined version than the one that we've seen in pictures this year, because those ones look much more refined.