When encountering the same key in RO_VPD and RW_VPD, dump_vpd_log outputs both values (in that order).  While Chrome seems to do the right thing (take the first occurrence, ignore the rest) there's other consumers of vpd contents (eg. init scripts) that are not equipped to handle multiple occurrences of the same key.

Therefore I think it would be least error prone to remove duplicates already in dump_vpd_log.