Statues of Epicurus are known to exist, and at least one statue of Hermarchus as well.
One of the best sources to start in researching this is Bernard Frischer's "The Sculpted Word."
There is also an extensive selection of plaster copies of status of Epicurus and Hermarchus in the Archaelogical Museum in Gottingen Germany.
Important information about reconstructing the statues to original form is here: http://www.digitalsculpture.org/epicurus/index02.html
A video reconstruction (which does not appear to have the hand outstretched correctly) is here.