For circulated 1939’s, use the S in PLURIBUS to determine which reverse you have. If it has a serif, then it’s the correct RDV. If it does not, then it has the RDV used in 1938. In 1939, the RDV transitioned and depending on the Mint, this determined which RDV is the most valued. For Philly, the RDV for 1938 was used for a short period making these up to 10X more valuable even in a circulated state. This does not hold true for the other mints which got more mileage out of their older RDV die sets.
