I am a US citizen, if I travel to Seoul, can I get alient registration with a validation of 6 month

I am a US citizen working and living in Beijing, China, I booked on a group tour to Seoul.

However, I will need to apply for a Chinese visa to come back to Beijing. By reading the Chniese Embassy note, I understand I will need an alient registration card from the SK government valid for 6 months, Can I get it on my entry to South Kerea?