FWIW, I placed an order for an MR on Thursday. Today (Saturday) I got a call from the salesperson who provided my test drive. She said she'd found an LR AWD nearby that had been a test-drive car for $1420 more than the MR price. I ultimately declined that offer, although it was tempting. (AWD is a wash for me, given its advantages and disadvantages, leaving range as the big advantage to me, and I don't think I need 310 miles of range. The test-drive car had 1,000 miles on it and was built at least six months ago. I'm sure somebody will appreciate the bargain, though.)
Anyhow, the point of this is that you may need to ask specifically about test-drive or showroom cars, not simply inventory cars. As I understand it, Tesla is now selling many (most?) of its MR and better Model 3s from inventory, and AFAIK they don't discount those. It's the ones that had been displayed in showrooms and/or used for test drives that get the discounts -- and if the offer I received today is any indication, they can be significant, albeit with the downside of potentially lots of mileage on them already. You might also need to compromise on colors, wheels, or battery/drivetrain options.
The large discounts are on the demo cars. For inventory cars they are waving the color or wheel upgrade costs. At least that’s what they are doing in the Bay Area.