Yup - the documents they sent out to reviewers stated that the 970s had 64 ROPs [1]. This was also further pushed down the line to the OEMs building the cards, who used it in their own advertising (see the chart from ASUS in [2]).
NVIDIA advertised the cards as having 64 ROPs - the fact that the first bunch of dupes parroted it to a wider audience is irrelevant.
Why didn't the OEMs catch it? You'd think they would verify the specifications of the chips they are given to some degree to assure they are accurate. Have they grown complacent?
OEMs only care about the external interfaces on the chips, and only if they're doing a custom PCB rather than using NVidia's reference design. It's not like they're advertising it as their own GPU - they put NVidia's name and logo all over their products.
NVIDIA advertised the cards as having 64 ROPs - the fact that the first bunch of dupes parroted it to a wider audience is irrelevant.
[1] http://www.techpowerup.com/209339/gtx-970-memory-drama-plot-...
[2] http://www.hardwarecanucks.com/forum/hardware-canucks-review...