That source ony says: “After distinguishing himself as bold and aggressive commander at Brandy Station and Aldie, Pleasonton promoted him to brevet brigadier general despite his lack of command experience. With this promotion, Custer was assigned to lead a brigade of Michigan cavalry in the division of Major General Judson Kilpatrick. After fighting the Confederate cavalry at Hanover and Hunterstown, Custer and his brigade, which he nicknamed the “Wolverines,” played a key role in the cavalry battle east of Gettysburg on July 3.”
Aldie was june 17, 1863
http://www.civilwar.org/battlefields/aldie.html
http://en.wikipedia.org/wiki/Battle_of_Aldie
Custer was promoted on June 29, 1863
Quote” Following General Meade’s replacement of General Hooker after the Chancellorsville debacle. Meade advised General Halleck in Washington that he would shake up the command of his cavalry in the hope of improving its efficiency. After consulting the Cavalry Commander General Pleasanton and accepting his recommendations. Meade wired Halleck an unheard-of request: -
“To promote - in one jump - three brilliant young officers from the rank of captain to that of brigadier general”.
These officers were:
Elon J. Farnsworth, 8th Illinois Cavalry
Wesley Merritt, 2nd US Cavalry and
George A. Custer, 5th US Cavalry.
Either Halleck approved in record time, or else Meade went ahead without his permission, for within a matter of hours Pleasanton had three new generals. Custer and Farnsworth were assigned to brigades of the Third Division to be commanded by Brigadier General Judson Kilpatrick, who was known more for his reckless bravery than his brains.
Custer’s promotion to Brigadier General, United States Volunteers, to date June 29 1863, two years after graduation, was even more unusual in that he was in fact only a substantive lieutenant. Brigadier General George Armstrong Custer aged 23 was at that time - the youngest General officer in the Union Army.”
http://www.americancivilwar.asn.au/meet/2004_04_mtg_custer.pdf
Finally, the date.
June 29, 1863, Custer Promoted to Brigadier General from Captain.
The very next day, June 30th, 1863, the newly promoted Custer and Farnsworth’s troops fight a battle with Jeb Stuart’s Cavalry.
Quote:
“ During the cannonading, Kilpatrick ordered Custer and two of his brigades from Michigan to attack the Confederates from the west side of town.
Dismounted, Custer’s men twice attacked the rebel positions south of Frederick Street using seven-shot repeating rifles, the first time such rifles were used during the Civil War, according to several sources.
Around 2 p.m., Stuart gave up the fight and directed his troops down Baltimore Street to what is now Fuhrman Mill Road before turning toward Jefferson, Wallace said.
By the end of the conflict, about 300 men were killed, wounded or captured. Townspeople cared for some in their homes. Eventually, four hospitals were set up in town for the wounded.
The engagement in Hanover kept Stuart busy for a day, delaying his arrival in Gettysburg until the second day of that battle . His mounted troops could have been used by Gen. Robert E. Lee to scout the battlefield, giving the Rebels better knowledge of the strength of the Union forces gathered around Gettysburg.”
http://explorepahistory.com/hmarker.php?markerId=1-A-1EB