Well for the selective service you would need a signature from the same time period to compare against before really drawing any conclusion.
You know, like college recor......
Never mind.....
See the differences in his signature appearing on the Selective Service registration and more recent (ca 2010)...the peace sign appwars to be made by the “b” being placed inside the “O”.
http://thehandwritinganalyst.blogspot.com/2010/10/what-does-barack-obamas-signature-tell.html