I am no expert but I don't think there is a difference between the two. I don't know why some have solex printed on them and others don't. According to wolf creek racing the same gaskets will fit both. Maybe it is like the nissan/datsun cars that popped up during the acquisition of datsun by nissan. The manifold does come with that price, assuming you are talking about the newer mikuni's. If you want more pictures pm me and I will send them.
Thanks