Good looking rifle, and two shots in one hole at 100 yds is nothing to sneeze at. Heck, I'd be happy with that at 25yds. Are you sure there's not a third 'hole' or ball mark in that group? That lower left lead mark sure looks bigger than .490" diameter.
I agree about that lead mark, and a three shot one hole group would be some fine shooting at 100 yards. I would tolerate the messy lube
. Be careful not to mess up that barrel with Pyrodex; clean very carefully and thoroughly if you must use it!