Yes, no, clearing up misinformation...
The ZC is not and was never available in the US market. The only ZC engines are the ones that are actually stamped "ZC" on the block. If the engine says D16A1, D16A8, or D16A9, it is NOT a ZC. Some SOHC non-VTEC engines were also stamped "ZC", like the block sitting in my CRX.
Not all DOHC D blocks are ZCs, and not all ZCs are DOHC D blocks.