The first # is the year. A 1990, 2000 begin with a "0", followed by the rest of the serial #. That signifies the XXX # set neck guitar they've made. There is usually a slight gap between the first and other #s.
For example, I have a guitar made in 2000. It's serial # is 0 52XXX, meaning it's the 52XXXth set neck guitar, and it was made in 2000. So, your guitar, that's 0 50648 is right in line with that serial # range of that year.
In 2008, they began using an addition "0" at the beginning of the serial #, to avoid confusion with the 1990-99 guitars and the 1985-89 guitars. My 2008 guitars serial #s are in the 08 135XXX-140XXX range...
Hope this helps..
Jamie