They probably didn't have any floor soundproofing either, or even carpet, which simplifies things significantly. I was amazed at how effectively the mass-loaded

They probably didn't have any floor soundproofing either, or even carpet, which simplifies things significantly. I was amazed at how effectively the mass-loaded vinyl soundproofing and carpet deadens road noise when I drove my car with bare metal floors recently. I would never buy a car without it. (The sunroof drains got disconnected and the floor was completely flooded. With the sound deadening mat under the carpet there's no way it would have dried out on its own, and it took me a few days to get it all dried out, so I drove it in the meantime with no carpet.)