Is it realistic to beat the battle tower without minmaxed EV training if you bring a good team of strong pokemon with well-balanced movesets?

I ask because in gen 3, GF hinted towards the value of natures, but never really gave players info about EVs. So, they would have to expect that the vast majority of players would go into these facilities with pokemon with maxed out EVs, but not minmaxed EVs by any means. I'm not sure if enemy teams have 252/252 EV sets in the tower, but would be interested to know this, since it would show that GF had this intention with EV distribution from the start.