There's no guarantee that it represents a hydrogen wall, but the consistency is difficult to ignore. You might get proof in time, too. The team plans to keep observing the unusual signal roughly twice a year for as long as the New Horizons mission continues, and researcher Randy Gladstone told Gizmodo that there's a chance the probe could image the wall in time.
Don't expect to learn more in the immediate future. Although New Horizons is a relatively fast spacecraft, it will still take about three more decades to reach Voyager 1's position at the very cusp of interstellar space. And if NASA decides against continuing the program, this signal may be about as good as it gets.