Logically speaking if an applicant happens to be in a different location than his VO, then, turning in documents etc should be an option, but then again how many logical things have we seen in this long process so far? my suggestion is to call the local VO where the applicant happens to be and ask them them if they are authorized to place that stamp or purchasing a plane ticket will be needed to achieve that process, my guess would be the 2nd one to make the bureaucratic aspect of this process less complicated.
so no one knows how long the stamping process takes?