The RCS measurement facility looks pretty similar to what USA uses. The transmitter antenna is located halfway on the strip in the DRDO facility. 
people are so fking wierd!! Everyone knows its not a prototype but attention hungry people are still calling it a prototype. Its a full scale 1:1 engineering model. Just a mockup for RCS testing and fine tuning. Probably the one made by VEM.
They aren't technically wrong. That model is likely a high fidelity engineering model i.e. it closely resembles the finished prototype. It just can't fly. Here's why -
You don't use a full scale model for geometric RCS estimation, that's done early on.
This is what you look for in a full scale RCS test :
1. Accurately representation of RAM coatings/RAS.
2. Surface gaps, fasteners, manufacturing tolerances, and panel joints
3. Engine inlet treatments and exhaust features
And remember, AMCA has a baked-in RAM i.e. RAS, so those would be required to be manufactured at full scale.
This things are hard to catch with a subscale model because they use frequency approximation technique i.e. to mimic the impact of X-band, they would use something like high MMW.
