Equatorial African States

Below You can find screenshots from Krause SCWC 1901-2000 44 Edition.

First is for  Central African States

Second is for Equatorial African States

As You can see territory of the unions is not the same (although bigger part is covering) it is not just the change of the name so I think those two should be separated as single issuers.

Maybe I'm wrong, but I think DRC was not in BEAC 1961-1973. Is it possible their map is false?

I close until proof

The map is not very clear, but I believe that the only difference between both maps is that the Democratic Republic of the Congo is colored on the map of the Equatorial African States. This is a mistake, as the Democratic Republic of the Congo had their own currency and never used the CFA franc.

According to the Wikipedia article, the Equatorial African colonies and territories using the CFA franc were Chad, French Cameroun, French Congo, Gabon and Ubangi-Shari (modern-day Central African Republic). These are the same countries that are currently member of the Banque des États de l'Afrique Centrale (see the official list), except for Equatorial Guinea, which joined in 1984.

The split into two sections in the SCWC is probably due to the change of name of the bank changed from “Banque Centrale des États de l'Afrique Équatoriale” to “Banque des États de l'Afrique Centrale” in 1975. Since the member countries didn't change at that time, it should not be considered as different issuer.