Hi
Is there any other information you may be able to add such as parents names, siblings names, etc?

I did a search on the Minnesota Historical Society Death/Birth index

http://people.mnhs.org/dci/Search.cfm

and was able to find a Robert George Gilbertson born in 1917 in Hennepin County. Do you by any chance know his middle name?

Add what information you can and maybe some more leads can be followed.

Leslie