I really haven’t heard of or know of such cases.
However, there are some cases where very low dose (by bodybuilding standards) testosterone use has had remarkable fat loss results. That isn’t usually the case, but the rate isn’t negligible. I don’t know if this is always the case but my observation has been that the remarakble resuls has happened with endomorphs only; very moderate benefit sometimes to mesomorphs.
So since HCG raises T I suppose the same thing could happen for those that would experience it with T.
With the exception of the few endomorphs that it makes a big difference for, that would not be a really big contributor to fat loss.
Maybe this is the same thing that happens with some boys as they pass puberty: most fat kids stay fat, but a few real butterballs lean right out past puberty, so apparently for some T makes a big difference for bodyfat. (It makes some difference for everybody.)