Yes, the building at Musick Point was indeed a memorial to Captain Edwin Musick and his crew, who were lost when their flyboat exploded in midair near Samoa. The Sikorski FB had fuel problems and was thought fuel vapour caused the explosion, there were no survivors.
The building was shared between the CAA coms (ZKLF) and the NZPO coast radio station (ZLD). ZLD/Auckland radio monitored 500 k/cs morse, and 2182/4125 k/cs r/t. I've only ever visited Auckland once, during the mid 70's and my only view of ZLD was from a tourist launch during a harbour cruise. The weather was crappy and we were lucky to see the station clearly up on Musick Point headland. We did go UNDER the harbour bridge, but never got OVER it.
NZPO coast radio stations were: ZLB/Awarua radio (where I worked), ZLC/Chatham Islands radio (ditto: '68), ZLW/Wellington radio, ZLD/Auckland radio, are all history now since the early '90s. Gone, are ZMV/Milford Sound (radiotelegraph and toll/rt*), ZLG/Haast (radiotelegraph*) and ZLQ/Scott Base (radiotelegraph*) by the late sixties. [*via ZLB]
TEAL flyingboats also worked ZLB at some stage, but well before my time.
Awarua radio was situated approx 8.5 miles south of Invercargill, on the In/Bluff road.
Cheers and thanks for jogging my memories.
Bazza B)