Okay, gang, I'll be the first to admit that I'm just not into knowing which model of sleeper I'm in at any time, but I will say this: whatever change came about sometime after 1980 was a definite plus in terms of quietness. I rode a sleeper on one of the Silvers around 1980. The interiors were light brown and tan, as I recall, and were all metal. Everything rattled and buzzed for the entire trip. I had to stuff every bit of toilet paper into every door just to abate the noise. It was so bad that I begged my company to get me a plane ticket home (and I really HATE flying...).
The combination of plastic and carpeting was a big improvement. No question, carpeting is impossible to keep clean, though. I just think about other things.