From the record
“The Cassidy House is located at 4121 Canyon Lake Drive in Rapid City, South Dakota, and is on the National Register of Historic Places. From 1947 to 1950, Lustron manufactured enameled steel homes.”
Wikipedia article Cassidy House (Rapid City, South Dakota), CC BY-SA 4.0.
One of 59 National Register listings published here for Pennington County · listed in 1998 · category: Building · built in 1949.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service · the Wikipedia article