Are these courses graduate level?

[jsd]

Apparently, yes:

XLC 200 to XLC 299; XLC 400 to XLC 499: UCLA graduate and professional level courses in which Extension students enroll. Credit earned in graduate study through concurrent enrollment may be used to satisfy requirements of higher degrees at UCLA and at other institutions at the discretion of the student's graduate division, department, school, or program advisor. (Applicability rules at UCLA are described in the publication Standards and Procedures for Graduate Study at UCLA.)

They go on to state that 500-series is doctorate level.