The MAG has been available in different versions to accept either the regular disintegrating links or the German DM6 belts. I'm not sure who has used the latter, though.
I'm pretty sure Rhodesia used disintegrating links in their MAGs and that is just a coiled radio wire in the picture.
Haven't found anything definitive on Rhodesia's use but, non-disintegrating belt. I believe that what appears to be a handset is actually the starter tab. You wouldn't walk around the brush with a dangling handset getting tangled in everything.
Also appears to be hanging straight from the feed tray, not off the front of his body.