First: Terminology: "bok" in springbok, gemsbok, blesbok, etc. refers to the original Afrikaans general term for all antelope. Very few of the Africa animals were formally named by English folks as the interior and wilderness of South Africa was explored and opened by my ancestors the Afrikaner Boer.
The "buck" in the English rendering of antelope names is merely an onomatopeoia - or sound imitation of the Afrikaans name. There is in fact no real, formally accepted name like springbuck or bushbuck. The real name of the bushbuck is "bosbok".
Amongst these eight animals in this category are the most hunted game in South Africa, namely impala, blesbok, "bushbuck", springbok, "reedbuck" (rietbok) and mountain reedbuck. The grey Rhebok (ribbok) is rarely hunted and neither the bontebok - the latter for having been on the local endangered specie list for very long.
The bontebok and the Cape mountain zebra enjoy the privilege that large conservation areas were set aside dedicated to each of these two almost extinct species. Like the black wildebeest and blesbok both are uniquely endemic to South Africa, and in fact unique to particular habitat areas in the south eastern part of the country. Today limited trophy hunting only is allowed on them and the money earned on that is used to relocate more and more of them as numbers allow.