Resumo: Não .
Esta é uma citação de John Peltier em seu site :
There is no automatic way to align a legend with anything. You can manually align it, and if the chart changes you are likely to have to realign it. Click on the legend and drag it with the mouse so the top of the legend (or bottom) lines up with a gridline. Then click on one of the resizing handles on the perimiter of the legend, and stretch the legend so that the legend entries are aligned between gridlines.