Insanely Awe-dical

In Joey Season 1, Episode 8, there is a discrepancy. In the first 10 minutes, there is an old video of Michael playing baseball in little league, he hits right-handed. Later when he is in the batting cage, he practices his swing left-handed.

I wonder if there is some study that shows if people can grow up with a preference for one hand, and end up using another hand. Perhaps precision/strength hands also have differences...