Step Parent Adoption in the state of Illinois

To Whom it may concern, I have a few questions about a Step-Parent adoption in the state of Illinois. I went through a divorce in 2007. During our dissolution proceedings, my Soon-to-be Ex-husband signed over his parental rights of our set of twins, which would be 2 of our 3 children because he was not the biological father. He was to sign the papers to have his name removed from the birth certificates and send it in to the Kansas Office of Vital statistics since they were born in Kansas. How do I find out if this was done? My current husband would like to adopt my children, but I know that this was one of the steps that needed to happen. I can take care of everything else on my end. Do I need to order birth certificates for my children to see if his name is still on the birth certificates. If my Ex-husband has not taken care of this, what documentation does he need to send in, or what documentation would be needed from me? I have our divorce decree that states that he is not the biological father and that all his parental rights and responsibilities are terminated. Any assistance would be greatly appreciated. Charvey71909@gmail.com christina.r.harvey.mil@mail.mil