If it's a US-specification Spitfire, all four front lights (L594 "beehive" glass lens) side lights inboard, flasher outboard on each side) were clear. Midway through the original Spitfire 4 production, Triumph began using the larger flasher lamp (L691 lamps, I think) with the plastic lens, but still clear.
Certainly, amber lenses were and continue to be available for both lamps, and many consider it a worthwhile safety upgrade to go with amber flasher lamps (front and rear).
US-spec. Spitfires always had the larger L691 flasher lamps in the rear, while home market cars used L594 lamps there.