In fact there are some Persian/Arabic fonts in TL08 and there is no need to
include them. They are a part of xepersian package. I think they should be
at fonts/truetype/xepersian

These fonts include SIL's font in addition to farsiweb fonts.

Looking at CTAN, it seems that the author of xepersian is not going to
include these fonts in his next release.