They'll have an interesting time proving that one -- however, to many of these folks, two or three examples in two or three different locations (irrespective of timeframe) are enough to "prove" a theory. The rest of the data is inconsequential and may be discarded.

Temples come in all sorts of shapes and sizes. One good counterexample would be the Mayan/Olmec temples; another would be the American Indian sacred sites (which served the same function as a temple.)