I think they did not use reduced/FLEX thrust.
FO Polehinke is attributed as saying something about FLEX in the CVR at the gate:
Polehinke: (5:56:34) Right seat flex takeoff procedures off of um ... he said what runway? One of 'em. Two four.
But according to the NTSB "Group Chairman's Factual Report"
www.courier-journal.com/assets/B257636117.PDF ref page 19
"The Operations Group determined that at the accident conditions of an aircraft weight of 49,087 lbs., a temperature of 24° C and a departure from runway 22 at LEX, the Thrust Setting chart indicated that a Reduced “Flex” Thrust takeoff was not available. The FDR indicated that the accident flight performed a full power takeoff."
The CVR transcript is here:
http://www.ntsb.gov/doclib/reports/2007/AAR0705.pdf ref Page 144