I am no Expert on Olsen but they did manufacture knives in their Michigan Plant--they also had knives made by other American companies--they contracted with Both the japanese and the German Companies too.
They have been closed since the late 1970s or early 1980s and the company Trademark is still for sale.
I forget who called me the last time but it seems that nobody wants to buy it.
I know I don't.
I'm sure Bernie Levine can shed more light if you ask on his Forum.
You might also ask Dave Shirley on the Northwoods Forum Below.
Dave is from Downstate Michigan and may know more about Olsen than I do.