The presentations from that symposium have been published by ACM:
ASPLOS-I Proceedings of the Symposium on Architectural Support for Programming Languages and Operating Systems, March 1-3, 1982, Palo Alto, California. ACM Press, 1982, SIGARCH Computer Architecture News 10(2), SIGPLAN Notices 17(4)
The IBM 801 was presented by George Radin: "The 801 Minicomputer", pp. 39-47.
You can download freely all the presentations from:
https://dl.acm.org/doi/proceedings/10.1145/800050
There is somewhere online an interview with one of the ARM designers, I do not remember whether with Steve Furber or with Sophie Wilson, where they mention how they have learned about RISC from this symposium.