@AncientJoe, those coins are clearly different die pairs. Therefore, they're not duplicates. Seriously, both are great coins, and I don't see a problem keeping both.
Great coins, everyone! I think I will indeed keep both denarii. My main issue is that, so far, I've avoided duplicates entirely and have instead focused on upgrading coins. Having two coins of the same general type is a bit redundant from a historical perspective but I agree with the posts here that they're different enough to justify keeping It will now be that much harder to hold myself back from buying duplicate Tarentum nomoi... curse the engravers for making an attractive series!
I have the "Collection Claudius Côte" sale "Monnies de Tarente" offered by Ratto in 1929. There are many varieties of the "boy on a dolphin" basic type with horseman right or left, walking, running or leaping, various tiny figures (owl, Victory, grapes, dolphin, etc.) in the field, and so on. He had close to 500 varieties, so @AncientJoe , if you only have one you need to get to work! I only have one: Sear Greek 349. Vlasto 623. SNG Copenhagen 853, "Period V, 334-302 BC."