Hi, new to this site, but have had interest in coins and collecting since childhood. I am hoping for some info from the wise bunch here. I have what was represented to me as a genuine cob. From my internet search, it appears to be a Mexico 8 reale cob from the 1713-1715 era, but none of the date marks are there? I was told it was purchased in Key West from Mel Fisher's store in the 1970s (what they all say right). There was a silver loop soldered on at some point and it appears it may have been cleaned/polished to make it a better jewelry piece. It looks genuine to me, but since I know little about these, what can you tell me. It weighs 27 grams not including the chain. Please see pics and let me know what you think. Thanks!