The biggest news from Tesla's (NASDAQ: TSLA) update on third-quarter deliveries was undoubtedly its worse-than-expected Model 3 production. With just 260 Model 3 units produced, Tesla missed its target for third-quarter Model 3 production for 1,500 units by a longshot. But there was one area investors may want to take a second look at: Model X deliveries.Quarterly deliveries of the late-2015-introduced Model X hit a new high in Tesla's third quarter, coming closer to rivaling Model S sales.