Mint Mark Identification

I recently purchased a coin from the Republic of Guinea.

Kennedy Brothers Coin

I have identified a strange mark on the coin, potentially a mint mark, but I am unsure. On the reverse in the 4 o'clock position is the number "1000" encircled. This mark is on countless commemorative coins from the late sixties and early seventies.

Equatorial Guinea, mark on the obverse
Equatorial Guinea, mark on the obverse again
Republic of Guinea, mark on the reverse

I have read some references on colnect.com identifying this as a potential mint mark for an Italian mint called Gori & Zucchi in the city of Arezzo.

Can anyone confirm this or at least shed light on this prevalent mark?

Many precious metals coins with purity .999 have a "1000" written down to indicate its purity. I have a couple silver medals with a "1000". Now it is possible for a particular mint uses the cartouche format shown on your examples, and not necessarily as a mint mark but more of a design choice.

Цитата: "Limbru"​Many precious metals coins with purity .999 have a "1000" written down to indicate its purity. I have a couple silver medals with a "1000". Now it is possible for a particular mint uses the cartouche format shown on your examples, and not necessarily as a mint mark but more of a design choice.

​Thank you so much, great info.