Escalated to Bugzilla from IssueTracker
I've investigated and reproduced the bug in the enforcement of the GPL restriction on symbols exported from the main kernel. (The bug does not exist in symbols exported from kernel modules.) There will never be a RHEL3 kernel fix for this GPL restriction enforcement bug nor will the setting of CONFIG_MODVERSIONS be changed. The reasoning is that this would break compatibility with 3rd-party modules. Thus, OpenAFS is safe for the duration of RHEL3. Closing as WONTFIX, which in this case is desirable by the bug reporter.