Going into electric-car maker Tesla‘s (NASDAQ: TSLA) fourth-quarter earnings release, here’s the biggest question: How many Model 3 vehicles will management say it expects to deliver during the year? After all, we already know Tesla has about 400,000 deposit-backed reservations for the $35,000 vehicles. But the big mystery is how Tesla’s Model 3 production ramp-up will look — and thus Model 3 deliveries.