There are some details that are hidden due to the yellow cloth, but apart from what you mentioned, the planform scale of the geometry seems a bit different to GJ-11 which may convey a larger aircraft than GJ-11, and some aspects of the edge alignment are different to GJ-11 as well.
IMO, the GJ-11/Phantom Ray/Neuron/Taranis kind of planform and geometry is very much a standard one that is likely to be useful for many different sized aircraft -- but just like how a Boeing 737 and a Boeing 767 both "sort of" look like each other with very similar planforms, the scale and size of them are entirely different.
I wouldn't be surprised if this same flying wing stealthy planform configuration is also shared between different aircraft of very different sizes but with very similar aerodynamic geometries.
That isn't to say this model is definitely showing something real, or that it's definitely bigger/different to GJ-11, but if it is meant to represent a real aircraft as the original post claims, I wouldn't be surprised if it was a different, larger aircraft.
