I think the operative word from that Wikipedia article is "usually" - "the terminal leaflet is usually absent".
There are a couple reasons you are seeing no fruit. First, if it was pruned last fall, winter or spring. Chinese Pistache bloom (and fruit) on old wood. The second is that it is a male tree (so blooms but no fruit) or it is a female tree but no male tree is close by, so, once again, blooms but no fruit.
Chinese Pistache are favorite street trees in a lot of cities.
