Is This Property Rent Controlled?

[Geo Tan]

So I viewed a property today in the North Hollywood area and I was confused by what the person showing me the property said.

Basically, the property I viewed had one unit in the front (from before construction) and two units on top of each other behind that unit which was built brand new. So ultimately the seller bought the property with one unit in the front and renovated it along with adding two units behind it. When I asked about rent control issues with the property they said that since the front unit (built somewhere in 1920s) was vacant when they built the two units behind it, it is not subject to rent control?

From my understanding, as long as even a single wall remains from the old property, it's build year is the same as the original unit (1920s)?

Or I asked if she meant that the initial rent isn't rent capped but it will be after the tenant moves in but she wasn't sure and said all she knows that this property is not rent controlled...

Can anyone tell me if this lady is right?