Those are S-70C-2 helicopters that were built for the PRC. A deal was made for 24 helicopters in 1985, and they were delivered in 1987.Is that what (blackhawk) I think it is? Are they the older models before the embargo on arms sell by the US?
It was anticipated at the time that the PRC would buy quite a few more, but after the 1989 embargo that all stopped, including spare parts for the 24. Clearly, the PRC has gotten around that issue because they operate these helicopters to this day. They have had plenty of time to figure out what they need and how to build it, and they have the capacity to do so.
Over 4,000 Blackhawk helicopters have been delivered to 25 different countries.