Lol, wtf, pimping shake weights on here? I would hope the OP is not that retarded.
I train my arms evenly, but they are still not the same. My left arm is bigger relaxed, but smaller flexed. Also my left arm has crazy vascularity on the outside of the arm (ie most muscular) but next to no vascularity on the inside (ie front double biceps). So my left arm looks bigger when hitting a most muscular, but smaller when hitting a front double biceps. The opposite is true with my right arm, more vascularity on the inside, next to none on the outside.