Of course, stamping BLACK POWDER ONLY on the gun is the manufacturers way of covering his tush.
Of course there is black, and there is black...
Some time back on the MLF, some good photos of a C&B that was blown to He.. were posted.
Seems the owner looked at the Color of the smokeless powder and low and behold, IT WAS BLACK!!
Yup. He loaded her with a full charge in each chamber and BOOM!! no more gun. As I recall, he and those around him weren't seriously injured but they were Dam lucky.
That's why I think SharkByte's question is a good one. It's always better to ask the question and be safe than to guess (or trust the dummy at the Gunshop. You know, the one that would say "This har Bullseye powder are Black..."