Just got a comment that putting the peace sign upside down is like flying a flag upside down – it’s a signal of distress or the opposite of peace.
However, looking at this site – http://www.teachpeace.com/peacesymbolhistory.htm
Ken Kolsbun, author of the book Peace: The Biography of a Symbol, reported that Holtom expressed regret in not designing the peace symbol with the joyful lifting of arms towards the sky. For most of Holtom’s life he would draw only the upright peace symbol. Holtom requested that the upright peace symbol be placed on his tombstone in Kent, England. As shown by the picture of his tombstone, his wish was unfortunately ignored.
Holtom’s wish that the peace symbol connotation of despair be changed to joy is illustrated by the picture on the right. When the peace symbol is inverted the letter “N” becomes the semaphore code for “U” which could mean universal disarmament.