A time capsule from 1970 is opened. When it does open the music played is the same six note tune played during the Columbia Television Distribution logo. Columbia Television produced the series.
Several times Grace is referred to as a woman in her mid 30's. Melanie Chartoff was born in 1948, making her about 42 when the series premiered in 1990. It is revealed here both her and Martin Lewis were in the SDHS class of 1970, which would make her about 38 as of 1990. Timothy Stack was born in 1954, so he was indeed in his mid-30's in 1990.