Early rifle shipments from South Africa to Rhodesia contained rifles that had the South African crest on the receiver, along with some other markings around the rifle. Once these left South African service, the crest was drilled out completely and the other markings drilled just deep enough to remove them. Later R1 rifle shipments bound for Rhodesia left Lyttleton Engineering Works without South African markings, so there was no need to deface or remove markings. Most R1s in Rhodesian service DID NOT have the "sanitation" cut. Note that it was common knowledge where Rhodesia was getting its weapons from. Defacing the markings was simply and SADF administrative protocol as the rifles left service.
Someone cut the drilled the receiver to clone an early rifle, but I agree: that camo job does not look representative.