You're right!
The information I was going off was from the Shootout. Robert Pressley and Chad Little both qualified with 97 Thunderbirds, Spencer was in the Taurus, but reverted to his 1997 500 Thunderbird for the Shootout Qualifier which he won. Greg Sacks also ran the Thunderbird for the Shooutout Qualifier. Spencer then ran the Thunderbird for the Shootout itself. Screengrab attached is from the Qualifier.
By Happy Hour Spencer and, from what I can tell, everybody else except Little and Sacks were in the Taurus. Little, Sacks and one other driver ran the Thunderbird in the 500, but Spencer had definitely swapped to the Taurus.
Really good spot, Joe!