i would have it looked at, because if it is out of round it will vibrate and cause unwanted shuddering at certain speeds. i had a set of 18's on my old vs commodore that i bought second hand, they didnt look stuffed or damaged so i ended up getting new bushes ect. thinking it was everything but the wheels causing shakin, so i took them to a wheel specialist (any place like bob jane, beaurepaires ect.) and they put it on the wheel balancer and told me it was slightly out of round, so i took it to bob jane they sent it away... got it back and well... i dunno if it was fixed or if it was the other rim on the other side... i even changed them all over but was still shakin, ended up puttin my old wheels 17's back on... be careful when buying second hand rims, could end up costing you more than you were intending to spend...
cheers