California Code, Health and Safety Code - HSC § 1568.098

(a) A licensee shall not accept, retain, or store any deadly weapon, as defined in Section 1568.096, of a resident or licensee.

(b) A licensee shall not accept, retain, or store any of the following firearms owned or possessed by a resident or licensee:

(c) The licensee shall not accept, retain, or store a firearm required to be registered with the Department of Justice pursuant to Section 29180 of the Penal Code unless it verifies it is in fact registered with the Department of Justice pursuant to Section 29180 of the Penal Code.

(d) The licensee may accept, retain, or store a firearm that is otherwise required to be registered with the Department of Justice pursuant to Section 29180 of the Penal Code but which is exempt from the registration requirements because it was entered into the centralized registry set forth in Section 11106 of the Penal Code prior to July 1, 2018, as being owned by a specific individual or entity if that firearm has assigned to it a distinguishing number or mark of identification because the department accepted entry of that firearm into the centralized registry.

(e) Commencing July 1, 2021, unless it is an antique firearm, the licensee shall not accept, retain, or store a firearm unless the owner of the firearm provides to the licensee documentation that the person is listed with the Department of Justice pursuant to Section 11106 of the Penal Code as the registered owner of that firearm.