Sql Server output parameters
There is nothing special about OUTPUT parameters when it comes to "named parameters" or "ordinal parameters". In SQL Server this terminology this applies to the EXEC call and how you specify parameters there: not direction


Ordinal = position must match and datatype must be compatible 
Named = assign the local value to the stored proc parameter name. Only datatype must be compatible


This is ordinal

declare @bob as int, @rich as char(20)
--OK
exec test @bob output, @rich output
GO

declare @bob as int, @rich as char(20)
--Fail
exec test @rich output, @bob output


This is named

declare @bob as int, @rich as char(20)
--OK
exec test
      @ID = @bob output,
      @mark = @rich output
GO

declare @bob as int, @rich as char(20)
--OK
exec test
      @mark = @rich output,
      @ID = @bob output


If you had a stored proc with parameters with defaults ...

create procedure test2
  @ID as INT output
 ,@filler1 tinyint = 0 --has default
 ,@mark as char(20) output
 ,@filler2 tinyint = 0 --has default
as
     select @ID = 5,@mark='test'
go


.. then you need the DEFAULT keyword for ordinal parameters if you have subsequent mandatory parameters

exec test2 @bob output, DEFAULT, @rich output --don't need to do anything for @filler2


For named parameters, it can be DEFAULT keyword or ignored because order is irrelevant

exec test2
      @ID = @bob output,
      @mark = @rich output,
      @filler2 = DEFAULT

exec test2
      @mark = @rich output,
      @ID = @bob output


And the obligatory MSDN link