Spanish eastern front bravery medal - Near Mint

[Anthony N]

Just been sent this Blue Division bravery & commemorative medal, unmarked but in near mint condition.
I noticed the top of the ring has a flat top with a slit through it. I checked my other medal that is marked "1" & it has the exact same feature. Has anyone else noticed this on their medal? Last photo will show it.
Ant.

[Anthony N]

2

[Anthony N]

3

[Anthony N]

That flat top i was mentioning, would be grateful if anyone could check their own medal.
Thanks, Ant.