He wrote he thought he could distinguish the following differences:
- The circles under the laurel leaves (if that's what they are) are a different shape. One is more rounded and the other more oval.
- The cross is fatter in one.
- The F in RF seems different, I think in the lower of the two horizontal strokes.
- The lines on the back of the neck seem different.
- While the cross-hatching is almost identical there are small variations.
Can you as well? I believe the circles and the cross varieties are the most obvious. Most intriguing! Question remains of course: What happened and why?