Yes it is, but magic weapon mastery is a magic-talent skill, not a druid-talent skill. So you can train it with the regular combat magic talent and don't have to pay nx to get druid talent to get 2x training for it. (Though, Druid still gives 2x training for it like other magic skills). That is probably the reason why it is not made a huge deal in the teaser site.
It's super super easy to train anyways. All of the druid skills are mind numbing.