Can the same hero get hit by two McCree high noon bullets?

Yes*

If you walk into the direct line of fire between McCree and one of his locked in targets, you will intercept the bullet meant for the person behind you.

McCree's Deadeye is a hitscan attack that charges at a rate of 170 damage per second.

In this video at 0:11, you can see a Roadhog with full lock (600+ damage) survive Deadeye because a Reinhardt walks in front.

While this does not directly prove the point, as Reinhardt gets one-shot by the 600 damage bullet meant for Roadhog, and only one bullet is fired, if Reinhardt had spent any more time in front of Roadhog, a second lock on would start for the Reinhardt, and both would hit him.

I'll back this up with a .gif showing this when I return from work.