From the May 2nd financial results letter:
"We continue to target Model 3 production of approximately 5,000 per week in about two months, although our prior experience has demonstrated the difficulty of accurately forecasting specific production rates at specific points in time because of the exponential nature of the ramp."
http://ir.tesla.com/static-files/1b240f1e-b519-4b40-b14b-fea...