The IRS clarified this and said it would be the next day. So if you take delivery on the day new guidance is released you can rely on current guidance.
From FS-2022-42, December 2022
"Beginning January 1, 2023, eligible vehicles may qualify for a tax credit of up to $7,500. Until the day after the Treasury Department and the IRS issue proposed guidance on the critical mineral and battery component requirements of the new clean vehicle credit under § 30D, the credit is calculated as a $2,500 base amount plus, for a vehicle which draws propulsion energy from a battery with at least 5 kilowatt hours of capacity, $417, plus an additional $417 for each kilowatt hour of battery capacity in excess of 5 kilowatt hours, up to an additional $5,000 beyond the base amount. In general, the minimum credit amount will be $3,751 ($2,500 + 3 * $417), representing the credit amount for a vehicle with the minimum of 7 kilowatt hours of battery capacity. Once the Treasury Department and the IRS issue the proposed critical mineral and battery component guidance later in 2023, additional requirements will change the amount of the credit (that is, an eligible vehicle may qualify for more or less credit than before). The credit amount will depend on the vehicle meeting the critical minerals requirement ($3,750) and/or the battery components requirement ($3,750). A vehicle meeting neither requirement will not receive a credit, a vehicle meeting only one requirement may be eligible for a $3,750 credit, and a vehicle meeting both requirements may be eligible for the full $7,500 credit. The Treasury Department and the IRS anticipate issuing the proposed guidance in March."