As far as I know the updated version was supposedly fitted from the start of the 69 season on Triumphs, but that needn't necessarily be strictly true.
All the 69 Triumphs I've worked had the newer version, but it's conceivable that the old Concentrics
were fitted at the start of production for that year.
The bigger tickler came later, even the early 750 twins had the small one, but I don't know when they changed over.
Triumph switched to Concentrics
sometime during the 67 season.