Consolate verification seal of State of Ill verified birth certificate

My daughter and son-in-law are students in China. They returned to the US in the spring to have a baby born in April. In July they returned to PRC with their baby. The baby was given a 90day visa. It was issued at your Chicago office after they submitted the passport and Illinois state certified birth certificate for the baby. They are now in there and are applying for an accompanying type for the baby. They were told they need a seal from the Chicago consulate for the birth certificate. We have a duplicate Illinois certified birth certificate for the baby and the state certified letter in our records along with scanned copies of the passports and visas of my wife, son-in-law and the baby's 90day one. We plan to come to your office Tuesday, Aug 20. Will you be able to supply the consulate seal to the baby's birth certificate? We will then mail it to our family in PRC. The office there said this will be ok.

Can we obtain the seal on the same day we come to your office? If not, can we leave an envelope to have the seal sent to us?