Yes, but they don’t apply to the general public. For example, waiting period exemptions include the following:

Firearms dealers and persons who have obtained special weapons permits issued by the DOJ are exempt from the waiting period.

Persons with a Curio & Relic collector's licenses issued by the ATF and who have a valid Certificate of Eligibility issued by the DOJ are exempt from the waiting period.

Peace officers with authorization from the head of his/her agency.
(Pen. Code, §§ 26950-26970, 27650-27670.)