From the record
“The Giles Gilbert House is a private house located at 306 N. It was designated a Michigan State Historic Site in 1984 and listed on the National Register of Historic Places in 1987.”
Wikipedia article Giles Gilbert House, CC BY-SA 4.0.
One of 3 National Register listings published here for Montcalm County · listed in 1987 · category: Building.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service