When I bought the 1969 Uruguay commemorative, it came with a card that describes the symbolism of the coin, shown in the picture below. Interestingly, it's mostly in English. No explanation came with the card, so I don't know if it's something "official" or not. I know absolutely nothing about it. I have visited Uruguay, eaten milenesia, chivitos and walked through Plaza Independencia, complete with the amazing Palacio Salvo. I also watched the stars at night on the beaches of Cabo Polonio, a place with little to no electricity. After that trip, I can vouch that Uruguay is definitely an underrated travel destination.