I think it's a smaller version of the radar that's mounted on Type 052D, probably for better stealthy target detection. Maybe @Tam can help us here?
They really are building 20 more.
It feels waste especially if they are not significant improvements from the original 30 batch. They might be stuck with 50 inferior vessels in the end when compared to their 054B/057
Progress update on one of the early 054 units. Some had hoped a forward VLS would be installed in the step-up structure just forward of the bridge, but that now likely will not be the case. The second image shows a turret ring being installed, most likely for a CIWS.
I don't know if that is a turret ring for a CIWS. It can be the remnant of the ring the HQ-7 launcher was sitting on. The HQ-7 isn't going to come back however.
The image below from months earlier makes me think the turret ring is newly installed. They will likely install the same missile CIWS found on 056 or a gun CIWS. Probably a gun CIWS, and maybe install the point defense missiles aft of the ship for greater coverage.