invalid CSS property

I got a CSS error in the source code for my site found in the PrintFriendly pf.php file–the double semicolon ending margin:

div.printfriendly {
            margin: 1px 1px 1px 1px;;
          }

The original code for this is on lines 224-226 in pf.php:

div.printfriendly {
            margin: <?php echo $this->options['margin_top'].'px '.$this->options['margin_right'].'px '.$this->options['margin_bottom'].'px '.$this->options['margin_left'].'px;'; ?>;
          }

Should the first semicolon in the last line be deleted?

https://ww.wp.xz.cn/plugins/printfriendly/