It doesn't look too bad., in spite of what the seller says about rust. A 4-speed manual makes it a rare survivor. In Ontario, it would have been scrap metal decades ago. https://bringatrailer.com/listing/1975-honda-civic-3/
Certainly a garage project, and nowhere near as nice as the previous one of these (which also had a larger Accord engine installed), but it's got 'good bones'. The rust underneath indicates to me it spent most of it's prior life in somewhere other than So Cal.
The period correct blue California license plate leads me to believe that the car could have possibly lived in California somewhere. The rust does not seem to be all that bad and remember California has a lot of shore towns and coastline so it could have lived near the beach.
Yeah, that license plate is vintage 1974-1975 all right. It's listed as being in Tustin California, which is near Huntington Beach\Long Beach and absolutely is considered "near the beach" so if a car like this sat in a carport or a garage for long periods of time, the rust would definitely be present. It's not bad rust in slightest, looks typical of a car from the era that lived a life near the beach.