Hey this is how it works for Pokemon that received a new ability in 4th Gen:
If the PID ends with 1, 3, 5, 7, 9 or B, D, F it is ability 1.
If the PID ends with 0, 2, 4, 6, 8 or A, C, E it is ability 0.
Just want to make sure before I moot out what I've been hatching so far O_o