Yes, it's a smooth bore brass. Supposedly it will fire either a .69 ball or shot.
I'm still trying to research what the charge should be. I've seen qoutes of 75gn, but that seems high to me.
@Dog&JeepThis site suggests rule-of-thumb for BP musketry etc should be like so: 50 grains FFG to .50-cal ball, 75 grains FFG to .75-cal ball, and so on. Halve the number for a pistol. For your blunderbuss, give a half-charge of 34 grains FFG, see how that does you, and then work your way up to something you like. But don't go over 69 grains.