Is there a difference in the black powder used in a flintlock and a caplock?

I don't know if this is the place to ask, but I was just reading a book, and it made mention of someones concern that if his army was to use caplock muskets, they wouldn't be able to use captured powder from the other armies flint/matchlock guns. Is that true? I always though I was an expert on gun-related things, but I'd never heard anything like that.Is there a difference in the black powder used in a flintlock and a caplock?
Sirbobby has it right, the pan stuff is typically 4F, the finest grained. Pistols would use 3F and rifles or smoothbore muskets would use 2F. Single F is for cannons. As far as I know, none of the replacement powders for black powder work well for 4F, but that info may be out of date. The source of info which was mentioned seems to have it backward, that 4F wouldn't be in stock by people using caplocks. Regards, Larry.Is there a difference in the black powder used in a flintlock and a caplock?
The only difference I can think of would be the powder in the pan...it was finer in grain than the stuff in the pipe.