did any nazi ss guards come into the truth?

Yes, in fact several did, even knowing where they would end up. There are even some who showed favor to the Witnesses but remained in Nazi uniform so as to provide food, both physical and spiritual. Because this information is spread over several books, I will be updating this post as I read those other books.
This first quote is from the "Divine Purpose" book page 171.
"There were also cases of SS guards turning from Nazism and dedicating themselves to Jehovah God and thereafter suffering with their former victims, Jehovah's witnesses." 
There are many more examples in other books I will add later, but I will add a personal experience I am aware of. I had the great privilege to interview a German Brother just before his death a few months before turning 90. I had known this Brother for years and knew he had been in the Hitler youth, but that was about it. He knew I did video work and one day he asked me if I would record his story. We did it as an interview. This Brother was in Nazi Germany at age 6 at the very start of WW2, he was later inducted into the Hitler youth and his accounts are difficult to hear. He even spoke of planning to beat up a "Bibelforscher". Instead, when he confronted the Bibelforscher, what he heard touched his heart, the youth started to study the Bible and became a faithful servant of Jehovah. He died a few weeks after the interview was completed. That interview is now in the Watchtower Archives.