They don't quite look alike. If you look at it, MATO and Yamamoto's style always has Green with sharp eyes. His long sleved purple sweater looks quite loose and his pendant reaches up to his waist.
In Green's second attire, he wears a cape. He wears it through the Yellow chapters. He looks pretty cool with it.
Green's third attire, his gym leader uniform, is a green jacket a dark shirt. By this time, you could clearly see that he looks quite tall.
His fourth attire...well...it's the Leaf Green one.