It will get both like the 136. What the 138 might have instead of the 136, which I suspect, is the small Type 368 double sided AESA to replace the Pozitiv radar that's set above the hanger. This radar separates the 138 and 139 from 136 and 137 and all the other previous Pr.956. What this radar does is scan for antiship missiles flying low over the water. The radar is the eyes for it's close range defenses.
The original 136 and 137 lacked the Type 364 radar that's the eyes for the close range defenses and scans and tracks antiship missiles. As part of the upgrade, the Type 364 is added to both ships. The Type 364 is responsible for queing the HHQ-10s, Type 730/1130s and H/PJ-13s, along with associate radars for the guns towards low flying threats.
However compared to the Type 364, the Pozitiv-E radar is 3D while 364 is still 2D. The Pozitiv's X-band is probably superior over the Type 364's C band for this particular low altitude, surface search scanning. Higher frequency is more resistant to sea clutter.
Ironically, the PLAN was requiring low altitude search radars into their ships, and the Russian ship builders abided to this request by modifying the Pr. 956 design with the Pozitiv radar used on the Admiral Grigorovich class (interview with the ship builder said they believed the Chinese would order Admiral Grigorovich class frigates which considered Chinese requirements in mind).
Going back to today, the small double sided phase array which I will call Type 368, which we see on the Type 075, the last batch of 052D and the 054B is the replacement for the Type 364. This might operate on X-band, and has true 3D capabilities with scanning both elevation and horizon. Logically this radar is best to replace the Pozitiv-E from the 138 and 139. The only question is the power and weight requirements of the new radar on whether these can be supported by the radar mount.
Should this new double sided radar is mounted on the 138 and 139, this could give the ships better defense capabilities over the 136 and 137 even if the armaments are the same.