edw,
Type ll has the "foot of the 2 turns upwards"
Just compare your stamps under a magnifying glass, it soon should become apparent.
With respect.
Consider this.
If you were buying an engagement diamond, and the shop owner only allowed you to see it from 5 feet away, would you buy it?
If you think you have an error, identify the Scott number, then scan the stamp individually, around 600 dpi, then post the scan with your explanation of what you think is an error.
That way, we can be of most help to your investigations.

Good luck.