Not to make a major issue of it, but I've read Gerasimov's excavation report and autopsy report, and he definitely reports that Timur had reddish-brown hair. Further, the Timurid Museum in Tashkent has samples of Timur's hair, beard and eyelashes, which they describe as reddish-brown. Gerasimov's book The Face Finder describes his evaluation of Timur and points out his reddish-brown beard.

This is from Central Asian history professor Elena Paskaleva's piece on 1941 Soviet expedition to Samarkand to disinter Timur:

"The embalmed body of Timur was laid on its back with folded hands and stretched legs, his face was turned to the west in the direction of Mecca. There were still traces of muscles and skin tissue on the bones; several reddish-brown eyelashes and body hair have been preserved in the Timurid Museum in Tashkent."