Looks like I've answered my own question.
The FMIDs use a Zpppvrx naming convention, where ppp is the product and vr is version release. The FMID for the RTCS Kernel is ZOSZ120, so I'm at version 1 release 2.
If someone knows a way to display the version/release of RTCS, similar to the way we can do it in the PlexMgr with other products, please pass that on.
Happy Holidays Paul.
You have figured out the decoding just fine, but to get the details of the maintenance you have running on RTCS try this:
Issue the following console command:
F RTCS,PACKAGE MAINT KERNEL
The output will have the FMID, RMID and what PTF last updated the component.
Hope this helps and have a safe, healthy, prosperous and Happy New Year!