I have two 1972 half dollars that only have part of the usual "FG" initials on the reverse. Both only appear to have the lower half of the G visible with the rest of the initial being polished out. It is a actual mint error, and if so what type is it? And why did the exact same thing happen to both? Are these worth anything?
I'm not an expert on Kennedy's but if all is similar, it is possible you stumbled across two coins from the same over polished die. Chances are usually slim, but it is possible. Some say error, some say variety.