Still a side view, but looks like the black wraps under the cheek to me, can even see it in the lower lip. Is this what you see in person? Adult brachys can have some nice finnage, and like I said the black markings on cheek and throat can vary from what I've seen, being prominent at times and almost disappearing other times (or in certain individuals in a group). Also, I've seen some with black along the lower edge of the pelvic and anal fins in some moods. They should turn out to be really nice fish.
I've seen brachys called 'black throat suriname geos' in some places, just part of the thing where some people don't distinguish between them beyond calling them suriname, brasiliensis, red humps, and jurapari.