The headgear was simply known as the forage cap. It came in two shapes : the earlier broad-crowned type shown on the Empress figures and the narrower 'pork-pie' variety introduced in 1834. By the time of the Mutiny, the latter would have become universal and it is highly doubtful the former was still around, even if you accept the fact that old stocks were still being used long after the item had been discontinued. During the Mutiny, the forage cap would also have been worn with either a puggaree wound around it or a white cover with or without a neck curtain. Uncovered forage caps would have been a rare sight as the fighting mostly took place during the hot season.
The accoutrements on the Empress figures are also not correct for the Mutiny : the figures lack the waistbelt which had become universal by 1857, along with the pouch holding the percussion caps for the muskets and the 20-round expense pouch worn in front of the waisbelt mentioned above. .