I didn't even know that Remington made round balls, so can't comment on their performance. However, since the ball itself should not touch the barrel because of the patch, I would think that the gold coating is not a concern. Also, if it were not benign and could harm the bore they would be open to law suits. A moot point since the company is defunct, but still valid in the context of whether to shoot them or not.
~Kees~