Yes it does.
Regardless of whether you call it -19.5 points or -20 points, a point spread that wide on an NFL game is as close to a lock as you can find.
According to data from SportsDatabase, 15 times since 1989 an NFL regular season game had a point spread of 17.5 points or wider. All fifteen favorites won, although they were only 4-11 against the spread.
This does not mean the Seahawks are guaranteed to win, of course. Their 92.7% WinProbability suggests they have about a one in 14 chance of losing.
Some day, a huge favorite like the Seahawks this weekend will lose. The chance that all 16 teams with a 92.7% WinProbability independently go undefeated is only 30%. Extend the sample out to 20 teams and the chance diminishes to 22%.
However, that does not change their chances this weekend, which remain nearly 93%.