I do not believe so. Sorry.

You can add a line break (by pressing Ctrl-Enter) after the label.  The result will look like top justification.  But the space below the label must be at least the height of the line break (see picture below).  

P.S. Visual Studio can align a button label any way you want.

How about some of old Richards magic paint the picture make the buttom tranparent put it over the picture.  May not be a one step solution but I bet it will look awsome with creativity.
Transparent Buttons

Kevin - that's a great tip with the line break. I might steal that for a video. :)

Juan - indeed!

You guys always come through for me!
Y'all are the best!
I've used that transparent button trick before. It was a long day yesterday, and my brain was fried. Thank you for reminding me!
Thank you, Kevin!!! This is the perfect solution for me this time!

You can also put a picture on a button so the label looks whatever way you want (see picture below).