The first two numbers should be a 3 and an 8, but the third number is unknown or I missed that post. So it should be anywhere between a Type 383 to 389, since Type 381 and 382 are already taken.
The first two letters designate what type and function the radar is, hence you have Type 34X, 36X, 38X, with X the final designate. Examples would be Type 344, 345, 346, 347, 348, 349, 361, 362, 363, 364, 366, 381, 382, and so on. 34X are fire control radars, 38X are volume air search radars and 36X are surface search radars.
There is a second dual faced rotating radar in the ship, and it's hidden inside the second tower, the conical base acts like radome. That one should be Type 368, based on a poster on a defense exhibit some years ago. The same radar now appears on the top of the mast of the last batch of 052D and on the second mast of the Type 075. Given the previous numbers Type 364 and 366 are already taken, this means the designation Type 365 and 367 were never used in an PLAN accepted radar. This means the final number is based on the number of serious proposals -- Type 365 and 367 might have been ultimately rejected by the PLAN --- and not the sequence of coming into service. Also, can't rule out the four sided possible X band radars on the mast of the Type 055 to either be filling the designation 365 or 367.
So it should be at least a 383, but anything goes if there are any number of rejected design proposals from firms competing for the same contract with each having a different 38X number.
Thanks. I wonder if they have specific designation for multifunction radar. As clearly the one on top is a multifunction, air surveillance and to control the new HHQ-16.
My take on the radars
The most visible differences tho is that 054B have no Type-345 CW Illuminator radar, previously seen on 054A. This indicates use of latest HHQ-16 with Active Radar Homing seeker.