The law says you must purchase the car AFTER July 1
Sec. 27. Electric vehicle rebate.
(a) Beginning July 1, 2022, and continuing as long as funds are available, each person shall be eligible to apply for a rebate, in the amounts set forth below, following the purchase of an electric vehicle in Illinois. The Agency shall issue rebates consistent with the provisions of this Act and any implementing regulations adopted by the Agency. In no event shall a rebate amount exceed the purchase price of the vehicle.
(1) Beginning July 1, 2022, a $4,000 rebate for the purchase of an electric vehicle.
(2) Beginning July 1, 2026, a $2,000 rebate for the purchase of an electric vehicle.
(3) Beginning July 1, 2028, a $1,000 rebate for the purchase of an electric vehicle.
(b) To be eligible to receive a rebate, a purchaser must:
(1) Reside in Illinois, both at the time the vehicle was purchased and at the time the rebate is issued.
(2) Purchase an electric vehicle in Illinois on or after July 1, 2022 and be the owner of the vehicle at the time the rebate is issued. Rented or leased vehicles, vehicles purchased from an out-of-state dealership, and vehicles delivered to or received by the purchaser out-of-state are not eligible for a rebate under this Act.
You can try applying but my guess is it wont go through.