They will tell you if the seats in first are all taken. Your chances are slim in that case since you are a 1P. Maybe even slim if you are 1K! Check the type of plane before you book. Your chances of an upgrade as a 1P are much much greater if the plane has a goodly number of first class seats. Flights to IAD from San Jose, CA have only 8 seats. Sometimes 1K's don't even make it what with all the Globals running around Silicon Valley.