My name is Charlie Kero, we have Kero relatives in Minnesota and Montana.Also my grandmother was a Luoma. Kero names in Montana could be John, Andy, Charlie (Kalle) Matt and Thomas / Americanized names.
There is a book titled At the Foot of the Beartooth Mountains by Leona Lampi ISBN 1-891403-06-0.This book is a history of the Finnish Community of Red Lodge Montana.There is a Jacob Kero mentioned in this book.There were lots of Finns in Montana who were miners.My great grandmother was there for awhile.My family settled in Raymond Washington, now some in Seaside Oregon.Astoria Oregon has a large Finnish population. Recently found grave site with the name Custaa Kero he died in 1957 or 58. My grandfather Kero was from Turku Finland.