How do I know if my Los Angeles property is RSO?

[Dereck San]

1b/1b Duplex (Built 1926)

1b/1b Duplex (Built 1926)

1 unit home (Built 1992, Single family)

*All 3 units on the same lot.

I'm recently was informed I need to post RSO notice for my property, I'm not sure if the 3545½ newer property is subject to RSO and I'm waiting for calls back from HCIDL Landloard Declaration department.

I'm know the duplex is under RSO, I wanted to only post the notice inside the hall so 3545/3547 can see it.

But I don't know if 3545½ is require since it's newer building. I don't want future tenants to get the wrong information.

I'm torn between installing a bulletin in a conspicuous place, Inside the hall for 3545/3547 see it or Outside by mailboxes for 3545/3547/3545½ to see?

Thank you in advance for any information.