Right, and they hit over 2000 a week about 2 and a half months after that (end of March). Setting an internal goal of 6000 per week (burst) in another 3 months from then seems appropriate if they want to actually achieve 4000-5000 per week in that time frame.
EDIT: If their production ramp doubling time really is 2.5 months, then based on the Bloomberg Model 3 tracker's estimate of 2600 Model 3s per week right now[0], they'll have about 4900/week by the end of June: https://www.google.com/search?&q=2600*e^(2.26*ln(2)/2.5)
I just don't understand this implicit idea that setting lower internal goals would actually help them achieve a higher production level sooner. That goes against common sense and experience.