New orange 2020. (Even a 6 year old used plug-in that had never gotten a decal would get a 2020. And now a low-income purchaser of a used plug-in with a pre-2017 decal can get a new one.)
The decal is from whatever the date is when DMV gets around to processing your application, which can be several weeks to more than a month after you mail it in, which would probably be when you get your plates and registration in the mail, several weeks after you buy the car.
If you want the decal as fast as possible, ask the dealer if they will apply for it (or already have), and ask them how quickly your car can be registered in the DMV system. If it's important to you, ask before you commit, when you still have leverage, and double-check with the finance person.
Once your VIN is in DMV's computer system, you can apply for the decal. The
DMV FAQ says to wait until you get your registration in the mail, but their Special Processing Unit told me they key off the VIN, not the plate. You can apply with the temporary plate as long as you've called DMV to verify that your VIN is in the computer.
