Would it be possible for you to share which Costco? I went to my neighborhood Costco but they seem to only have the R6900 and R7900.
This makes me wonder if they really have the Netgear Orbi, or some variant thereof. That would be typical of Costco, to have a somehow reduced version of a router, like the R6900 versus the R7000 or the R7900 versus the R8000. The R6900 and R7900 would still be said to be in the Nighthawk series, but are slightly different hardware. Since I don't see it at Costco online, can't tell, though.