That sign seems to be part of a myth.
“The fact that Irish vividly “remember” NINA signs is a curious historical puzzle. There are no contemporary or retrospective accounts of a specific sign at a specific location. No particular business enterprise is named as a culprit. No historian, 2 archivist, or museum curator has ever located one 3 ; no photograph or drawing exists. 4 No other ethnic group complained about being singled out by comparable signs. Only Irish Catholics have reported seeing the sign in America—no Protestant, no Jew, no non-Irish Catholic has reported seeing one. This is especially strange since signs were primarily directed toward these others: the signs said that employment was available here and invited Yankees, French-Canadians, Italians and any other non-Irish to come inside and apply. The business literature, both published and unpublished, never mentions NINA or any policy remotely like it. The newspapers and magazines are silent. The courts are silent. There is no record of an angry youth tossing a brick through the window that held such a sign. Have we not discovered all of the signs of an urban legend?”
http://tigger.uic.edu/~rjensen/no-irish.htm