In the Big O the campus was on California St. Then in the 70's the north loop of the interstate cut through and isolated the campus from the western part of the neighborhood. CU got permission to turn that 3-4 block section of California St. into a campus mall. the rest is history. Looks like all of California and also Webster Streets are now pedestrian malls.
Everything east of 24th st is basically new since the late 70's-early 80's, except the law school (44) and the Jesuit Residences (49). There used to be 2-3 buildings South of 480 (bottom of map).
Haven't been in Omaha since '99, so who knows.