No, his purpose was to show there was a wider world and a deeper history to Middle-Earth than we got to see in the books. Tolkien was dropping hints like that all over the story; Tom was just the biggest one.

It also was the way Merry got his special wraith-killing sword, and it gave a bit of a glimpse into the limitations of the powers of the ring, foreshadowing Sam’s ability to give it up freely.