Tesla Inc. (TSLA)  may finally be a "real car company" after  successfully hitting its production target, but analysts still weren't impressed.

"If this pace can be repeated, Tesla will turn into a self-funding company," wrote analysts at RBC Capital Markets. "However, we remain on the sidelines believing that a lot of the positives and a rosy future for the company are priced in."

RBC also noted that the road to make 5,000 Model 3 vehicles a week was a rough one for Tesla. "There were some extraordinary (bulls will say creative, bears will say highly unusual) means to get there ... most notably [the tent]." Tesla built a third assembly line in a big tent outside its main factory.

"In our view, the efforts taken (tent, overtime) represent a burst rate, not a yet sustainable pace," RBC said. 

Efraim Levy at CFRA Research cut his rating on Tesla to sell from hold. He left his price target unchanged at $300.

"We do not see this production rate as operationally or financially sustainable," wrote Levy. "However, over time, we expect the manufacturing rate to become sustainable and even rise. As usual, we expect the bulls and bears to largely reiterate their views after the latest development."

Levy expressed concern over reports that Tesla was asking for additional $2,500 deposits from Model 3 reservation holders "a little unnerving, as it seems to be an aggressive attempt to meet otherwise difficult targets of being cash-flow positive in Q3."

Tesla was trading down 2.5% to $334.21 on Monday.

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