So far there have been two developments. First, I made contact with the historian's office at the National Geographic Society and they are looking into whether or not they have a copy of the march and if anyone at National Geographic is aware of the march. So far it looks like the march was indeed lost.
Secondly, and more importantly for this blog post, I worked with pianist Grant Nakano to produce a music video of the song. Here below, is the piano version of The National Geographic March, which was previously lost to time
The march is definitely tied into my thoughts of the 1920s and 1930s with its band sound. I imagine an old silent newsreel showing explorers climbing a high mountain or showing some exotic land (a recommendation I may have to try is to attempt to read an old National Geographic article while playing this song in the background, maybe that will make the march "come alive").
I still prefer the "new" theme because its neo-classical feel seems timeless as opposed to Darcy's tribute song which sounds come from a closed era.
I will keep readers updated on whether or not the National Geographic Society truly forgot of the song.