Yes there are 3 different unicode encoded strings, and they are all slightly different.
There are 3 exploits in the pdf, each with shellcode to go along with it:
Collab.collectEmailInfo exploit
downloads from
--boomroot.ru/svy/load.php?a=a&st=Internet Explorer 6.0|Windows XP&e=2
util.printf exploit
downloads from
--boomroot.ru/svy/load.php?a=a&st=Internet Explorer 6.0|Windows XP&e=1
Collab.getIcon exploit
downloads from
--/boomroot.ru/svy/load.php?a=a&st=Internet Explorer 6.0|Windows XP&e=3
Good that u noticed the e=1,e=2,e=3 at the end of each exploit. Lets them keep track of which exploit downloads more frequently and stat tracking.