I believe the Gilbert 1903-1980 was the son of Gilbert and Louise. I found Gilbert Millsten, single in 1900 in Sacred Heart Renville County, Minnesota. In 1905, Louise Milsten is listed with her children Perna and Gilbert L, again in Sacred Heart.
In 1920, the following family is in Pope County
Gilbert Rust, age 38
Louise Rust, age 41
Ethel Rust, age 11
Florence Rust, age 8
Orien? Rust, female, age 5
Bernadine Rust, age 3 2/12
Pernille Milsten, age 19 step daughter
Gilbert Milsten, age 16, step son
Pernille Milsten died in Chippewa County on September 7, 1924. Her parents are listed as Gilbert Milsten and Louise Gerde.