Yes, but being a mere citizen is a necessary, but not sufficient, requirement to being constitutionally qualified to be president.
There was no indication in post 4231 by Calpenia that Presidential qualification was once again being brought into the conversation, so I commented only on the citizenship proof issue.
As far as B. Hussein Obama's status is concerned, he apparently isn't a naturalized citizen, having obtained citizenship though his mother and possibly Birth in HI.
If He isn't qualified Hillary will make it known on day one of the Commie Convention in Denver.