Of course. Anything you can learn, you can unlearn with the correct information.
To further my answer, in light of your specific question about unlearning shame over one's own naked body: It would not be possible for some to overcome conditioned shame, if the persons in question choose to remain in and involved in the environment that reinforces that shame. Some would not be willing to 'lose their religion', so to speak, in order to be free of clothing. Shame is a controller. It works well. There are also other societal pressures which cause certain people to feel ashamed of their naked body, such as television commercials and roadside billboards that advertise "mommy-rejuvenation" plastic surgery to help you look like a young maiden who's never given birth. We shame young mothers and mothers in general, the old, the overweight, the underweight, the non-Caucasian, the small breasted, the scarred, those with birthmarks, the maimed, and the disabled. Pretty much only wealthy, white females between ages 18 and 28, who haven't given birth, or who have had restorative surgery, can get naked nearly anywhere they choose without repercussion.
Therefore, in a society in which the majority support the laws governing indecency and agree nudity should be illegal, it will always be dangerous for even those without shame to bare the entirety of their skin, due simply to the fact that they would be subject to criminal charges, and be perceived, in their seldom seen nakedness, to be vulnerable. Clothes are armor against the perversions oppression creates. It's a vicious circle.
Thankfully, there are designated areas (such as nude beaches), in some countries, where people can feel the sun on every inch of their skin, and not surprisingly, these places are remarkably peaceful.