I own and play an E.L. DeFord flute from Elkhart Indiana, with the serial number 'D61639', and the number '2' beneath that (which I would assume is the particular model of my instrument). Does anyone know anything about DeFord flutes, and possibly about my model specifically? I am very curious, and a preliminary search yielded very little about it.

I had a DeFord Flute through out junior high and high school. My understanding is that these flutes were made by Emerson DeFord, the founder of Emerson flutes. As far as I know there are no new flutes being made under the name DeFord as DeFord retired in the late 1990s. So your flute should be the equivalent of a current day Emerson Model 2 flute.

Here are some links you may find helpful:
http://www.emersonflutes.com/
http://www.namm.org/library/oral-history/emerson-deford