\newcommand\pagenrframe[1]{%
  \iframe\sillyshape(134,500){1732}%
    {0pt}\ifrch\ifrcv pagenr:{%
      \sepbox(0pt,2pt,0pt,2pt){#1}}}

framed numbers like \pagenrframe{\oldstylenums
{21}} and \pagenrframe{\oldstylenums{25}}.