drum bearing assembly?

i got a indeset is60v tumble dryer, and the bearing shaft broke on it! i found replacement parts for it, nut it has a slietly different pice compared to what my current on has, it has a square peice of metal instead of a round bit, and i not sure what the differnce is, and if the square bit will be fine to fit, instead of replacing it with the same as it come with!1 any one changed a shaft bearing before and faced this problem, or know the answer??