Couple of question/concerns....
How were you able to find out build date without physically looking at the car?
Also, Like I mentioned before here, If I do take car that was built prior to price raise on paint, I shouldn't be liable to pay for it. Just my opinion
This twitter is pretty handy for getting close the date. I was told by Reid @ the Dallas Cedar Springs service center that June 18 was my car's born date but that appears to be impossible given the timeline in this twitter which looks to be early May 2018.
Model 3 VINs (@Model3VINs) | Twitter
In my mind that makes sense to pay less for a car with less revisions than a newer car with more revisions. I don't have high hopes for price negotiations. Just a hunch.