Here’s a video that every Kwanmukan student should see. It is from 1958 and shows Park Chull Hee demonstrating Jang Kwan, Lohai. and Kangsanggoon – Kusanku. Later on, Kim Soo performs Bassai Dai and some of the Heian kata. There is another demonstration of Jang Kwon at the end of the video.
In a group clip of punching, you can clearly see shoulder rotation in the kibadachi.

Video link:

https://youtu.be/T1B8Wz_CaRY?feature=shared