To which I assumed there was 1x T/R module per antenna, and there are quite a few antenna.
Another look at the AAM-4B seeker seems to show that the holes around the plate and on the stand are phillips screw sized, which to me indicates it is a missile sized seeker and not some obnoxiously large and pointless test device.
Spoiler
The PL-15E seeker by comparison has between 400 and 600 square antenna packed into those modules. Feel free to try and count yourself, of course, some are missing.
To break this down further so others can see what I am talking about:
Here you can see one of those square T/R module packs broken down. There is the case, the individual T/R modules, and the SMP connectors. I will post the image of the wreckage below which also has the SMP connectors visible where the antenna’ broke off.
Here are the packs that is what the exploded view above is depicting:
Here it all is together with the antenna squares on top:
And here is the complete thing on a test rig: