While Falcon 1 was developed on internal funding, the first two launches were paid for by DoD through DARPA. There was also a 15 million USD contract to launch a military satellite in 2005, that ultimately fell through (unknown how much was paid to SpaceX by the time of cancellation, but definitely not 0). In 2005, SpaceX boasted USAF as customer lined up for Falcon 1 launches.

Ultimately, first 2 launches the customer was purely military, and third launch by SpaceX was shared military / NASA / civilian client.