The short answer is no. However, audio effects or soundclips for Final Cut templates are "deposited" in the effect's "Media" folder upon Saving. They can be imported into FCPX from that location.
Of all the effect types that Motion creates for Final Cut, the Transition is the most difficult to provide this type of media for. If you think about it, transitions are applied to clips, often without "handles". Whatever time length you create your transition at, it is overridden by the default setting provided by your FCPX preferences. Transitions are very often resized or time-stretched in the storyline. With that in mind, where does the audio go? Does it start at exactly the start time you set in the template, or does that start time need to scale with the time-stretch. And if you have altered the timing of the transition, does the audio also get scaled? What if it's a "hit" type sound effect that needs to play with its exact original timing? There are far too many variables involved for Motion to be able to provide inclusion. Audio needs to be applied in Final Cut by a human who can make all these kinds of decisions.
The other kinds of templates are a little different (but Motion still does NOT include audio inside FCPX, it has to be applied by importing). There are timing markers that can be used to restrict how animations and audio interact. In this light, I've never understood why it hasn't been possible. Maybe, it's something even more simple: perhaps a licensing issue? Apple is just making sure that if you use copyrighted media, the responsibility is on you. Who knows? Apple never says...
If your audio is shorter than the transition (project length) and needs placing at a scaled reference point, I would suggest including a "cue mark" (if there are no other visual clues — a simple small shape of a few frames length) that can be turned on and off to assist in sync'ing the audio to the transition.