I came across this Spiegel Christmas catalog page from 1942 which shows a Marx train set that included a 12-piece set of Built-Rite cardboard buildings. Longtime blog readers know I had blogged these buildings from Oct 2011 to Jun 2012 with an update on one of the houses just last month. This page confirms that the set was indeed issued in the 1940s. As a side note, I never did properly blog the Business Block because I don't have a complete one. Enjoy!