Newbie here. I collected coins for many years but today my step daughter got a 1984 d half dollar with what looks to be the dates 1960 and 1985 stamped on the obverse and the reverse has what looks like to be a messed up 'E' in the word 'united'. I'm attaching pictures for reference. Does anyone know what the coin is? I am assuming it is altered and not any mint error.