I can't find it, but there's an episode from Christmas 1979, where a female contestant buys a car by solving SLEIGH BELLS RING ARE YOU LISTENIN'. For some reason, I wanna say that was a round one puzzle, but I could be wrong.
If there is something I'm missing to post a PNG screenshot I'd share it.
When was the top value in Round 1 increased above 500? I know it was 500 in the hour-long episodes, and cars were over $3000 at that point.