Hi @jehlp and welcome to the checkmk community.
The newer controllers are not recognized by checkmk because there ist another oid to check to determine the WLC device. We had this situation a few weeks ago and i created a pull request for the coding.
You can fix this by copying the file for the check (different directories between your versions) to the local path ~sitename/local/share/... and changing them. Take a look at the my pull request for details, if you need further help, let me know:
13611 FIX Add service detection for Cisco WLC C9800 · tribe29/checkmk@676234e (github.com)
There is even a difference between the C9800-L-C and C9800-C-L (appliance and virtual).
Please forgive my bad English, i am German 