That is what we in the trades, as a licensed contractor and a licensed Real Estate person/ Realtor, would call "Grandfatherd in". Only homes built today have to meet title 24 building codes. The state of california requires certain things to be done like the water heater to be strapped to meet earth quake reqirements for the fire departments, that smoke detectors be installed that meet standards of the time it was built. I mean a home that was built in 1950 had no detectors must now have a least one in the hallway near the bedrooms.
Your question has to do with engery efficiency and back in the 1950's it was not an issue. The new title 24 requirements are much stricter like the "seer ratings" of the air conditioning and the "duct sealing". Make sure your home inspector checks for these things. You are having a home inspection aren't you? Please say yes!
You can ask the seller to to do things like "Pay" to have these things done but they are only obligated to do the required things in the purchase contract , not bring it up to todays standards.
SMUD has some progams set up just for this issue and yes it cost somebody.... more