No, the Maine instructions merely refer to "direct obligations of the US Government, such as ... US Treasury bills and notes".  Silent as to whether must be directly owned by taxpayer, i.e. a direct obligation of the US to the individual taxpayer-owner of the instrument, versus taxpayer indirectly owning via a mutual fund,  
    Some other states have specific guidance as to a required percentage of a mutual fund's assets or income, sometimes a quarterly test, in order for the US Govt-portion of dividends to be exempt from state income tax.  
    Not sure where 'around here' is -- I was hoping some Lacerte users in Maine might know, since can't find any more specific guidance on Maine Revenue Services site!