Is a Triplex without building permits still a buy?

[N/A N/A]

I'm looking to buy my first piece of investment property out here in California. I've come across a Triplex selling at a deep discount. I've talked to the listing agent as to why it's selling so cheap, it's because the back 2 units, Studios, were built around 1970, and the owner at that time did not get permits for the addition to the property.

Would there be problems arising in the future for me after becoming the owner on this property without it's building permits?

Would I be able to get the back 2 units permitted after buying it through the city?

Thanks