Tesla board member Ira Ehrenpreis was the first to put down a $1,000 deposit on the Model 3 and gifted the car to Musk for his 46th birthday, Musk said in a tweet.
Musk has high hopes for the $35,000 Model 3, aimed at the mass market, and expects the rollout to help the company deliver five times its current annual sales volume.
Tesla's shares have taken a beating in the last few weeks, as investors have become increasingly concerned that demand for the company's existing Model S sedan is weakening.
Musk said in May that some "confused" Tesla buyers considered the new Model 3 as an upgrade to the Model S, hurting orders for the older car.
Registrations for Tesla's vehicles in California, its largest market, fell 24 percent in April from a year ago, according to data from research firm IHS Markit.
Separately, the Wall Street Journal reported on Sunday that new registrations of Tesla cars fell to zero in Hong Kong after authorities slashed a tax break for electric vehicles in April.
Last week, Musk said production of the Model 3 would increase exponentially — from 100 cars in August, more than 1,500 in September to 20,000 Model 3 cars per month in December.
