There's no reason not to drill the front to. I'd be inclined to take the fork off and use a pillar drill working from the rear to insure it's lined up.
I've got the original, unused, fork from mine, under the bed, if you mess up with the drill and need another...not trying to be a harbinger of doom, but if you need it, for the cost of postage it's yours. My frame is a large, but would guess the forks all have the same length steerer.
There's no reason not to drill the front to. I'd be inclined to take the fork off and use a pillar drill working from the rear to insure it's lined up.