No. John Demanjuk was found to be a guard and went on trial in Israel. He's still here and they are waiting to deport him.
There have been other cases.
The problem stems from trying to prove they were there. At the very least they can nail them on lying about their identity on their immigration papers.
He didn't mention Demanjuk, but every court that's looked at him says he was a camp guard. However he's being deported, since he entered illegally, not prosecuted. In general prosecution is done by the nation the crime was committed in. To my knowledge, run of the mill camp guards like Demanjuk aren't prosecuted very often.
"The problem stems from trying to prove they were there"
No, the problem stemmed from the forged Soviet supplied proof that Demjanuk was Ivan the Terrible. The Kremlin has made great gains by beating the "Ukrainians are anti semites" drum periodically.