Yup- that worked! I ended up just copying all the style from Genericons.css to get it to look exactly the same as the others.
.pis-comments:before {
display: inline-block;
width: 16px;
height: 16px;
-webkit-font-smoothing: antialiased;
font-size: 16px;
line-height: 1;
font-family: 'Genericons';
text-decoration: inherit;
font-weight: normal;
font-style: normal;
vertical-align: top;
content: "\f300";
}
Thanks so much!