Hi, anything built before 1978 most likely had lead based paint. Many will say that as long as there is no peeling paint you should be fine. The walls have ,most likely been painted many times, the windows sills, frames, and door frames are areas of concern. These areas in particular are common for peeling paint. If you decide to renovate and do any sanding you need to be aware that lead paint can be released into the air. Its best to have air quality tests done after the work is completed.