Looks like it's a 66 titled as a 67. It was common practice back in the day that the bikes were titled as the year they were sold.
Check your rear brake backing plate if it is chromed steel and not aluminum that would definitely make it an early 66 as the backing plates went to aluminum in 67.
Also if the brake and clutch levers are steel that would be another indicator of a 66, although they could have been changed out over the years. 67 and up had the alloy AMAL
levers with the star adjuster.
If you are a collector then in my view the 66 is the one to have, if it has the AMAL
GP carbs still on it you are in luck.