Nope, sorry but I believe you're wrong. The deadline for the Federal tax credit for Teslas is indeed December 31, 2019. After that you will get $0 from the Feds, assuming that nothing changes in the tax law between now and then. Based upon the 200,00th Tesla being sold in July 2018, the FULL $7500 credit lasts until the end of this year (12/31/2018). Then for the next two quarters (until 6/30/2019) it's halved at $3750. Then two more quarters (until 12/31/2019) it's halved again ($1875).
Tesla