Well......sorta. The first number is the weight before the oil reaches operating temperature. Once there, it is the second number.
I have assumed for years that the "W" stood for winter, but it does not. At least from what I can dig up on the net. The best that I can find is that it means "when cold" or before operating temperature.
At least, that's what I have gathered from most of the oil sites.
So basically, if you have 20/50, it is essentially 50 weight because that's what it is when warmed up.
At least, this is what I have inferred from reading. I could be slam wrong.
