My contacts say this was a special setup just for this story. All the stations pooled their choppers and shared each others feeds, so there were constant aerials of the cruise ship. One would go to refuel while another took its place. KGO offered to pool their chopper feed if they could use the other pool choppers (N62TV which is the one branded with KTVU livery, and N42SL, a generic news helicopter that seems to have replaced generic shared helicopter N75TV which looks to be in Sacramento right now.) It appears that KGO and KTVU are the only two that have full command of a chopper. The generic one might have some 50/50 shared command between KNTV and KPIX, which explains its lack of branding. I would assume Helicopters Inc knew that KTVU might not want to fly to everything KNTV and KPIX might want aerials of, and offered to let them share a generic chopper in addition to the KTVU share.
@rkolsen's helicopter project has uncovered some interesting sharing going on in the market. During the Garlic Festival incident is when the "generic" N75TV chopper was discovered, which all the stations were using, including KGO.