Series 2's built 58 to 60 but the reg for some may be later.
Some pointers to difference's.
Head lamps of 2's are proud of the grill,2a's are flush.
Vent flaps are opened with a turn knob on 2's, leavers on 2a's.
There were no indicator position pressings in the front wings on 2's. Most were fitted with indicators though and you may notice the lamps point up some as they were just screwed to the wing.
Horn button on a stalk on most 2's in the steering wheel on 2a's.