No wonder it looks too small to be the radar on 392. You mentioned that this radar is meant to replace Type 364? does that mean all those type 56 and type 54As are going to be refitted or just type 54As? I mean, the radar these ships are equipped with sure is ancient compared to their hull age. Another thing, is the radar a modular one like how many Western naval AESAs are? It'll be pretty neat if it's so.
I am leaning on the idea that the smaller radar would replace all Type 364 not just on the 054A but on every ship that has this radar, which means Type 052C and 052D, unless its not worth the bang for the buck. Like for example, Liaoning and Shandong also has Type 364, two located on opposites sides of the island. Other ships that have Type 364 includes the pair of 054, the 052D pair which are the very first ships in the PLAN to introduce the radar, the 051B refit, the 052 refit and the 051C. The Sovremenny refits are getting Type 364 too. However, I think all the ships that have been refitted to the Type 364 are not going to get refitted again as they will eventually expire later as a whole.
I am also leaning on the idea that the refits on the pair of 054 and 052B are on hold because they might be used as the first platforms to have the radars operationally. Kind of like this fan depiction of the 052B, although this one still has the Type 364 at the back. Just imagine it with the smaller two sided radar on the back like the fan drawn frigate on the previous post, and you're good to go.
As for the radar being modular I don't know. Being modular supposes the larger radar would be part of the Type 346 family and for the smaller one being of another radar, like the four faced fixed X-band set on the mast of the 055. Being modular would suppose it would reuse the modules and part of the back end of the other radars for reasons of economy and accelerated development, using proven blocks to build new systems.
However, both new dual sided radars can also be using modules that are newer in design, lighter, requires less cooling than those on the fixed AESAs. In which case, these radars would be another family entirely.