Excellent question. Several factors can affect the melting point of chocolate (room temperature and the beginning temperature of chocolate bar being the two most significant).
Fine chocolate melts at body temperature but if the bar starts at room temperature (around 72 degrees) then it needs to "warm" about 26 degrees to come to body temperature, if held in your hand. The holding of the chocolate bar in your hand is not the best method to determine "meltability of chocolate at body temperature" because the ambient air temperature is often so much cooler than body temperature.
The way we recommend is to bite a corner of the chocolate bar and hold it on your tongue and push your tongue gently against the roof of your mouth. Hold it there for a few seconds. This unequivocally brings the chocolate to body temperature and you should feel the sharp corners of the chocolate bar begin to soften. They won't go to liquid immediately but they will soften and begin to melt after a few seconds and this is the indicator we look for.