Flexplate help

I've finally got my parts together for my new motor and I'm kind of stumped on what to do about my flexplate. I got a built short block that has 0 miles on it from local guy. I talked to the machine shop that did all of the work before I bought it. They verified that they had built the motor. The guy I bought it from gave me a brand new scat flexplate that is weighted and an ati balancer. He said that the flexplate was balanced to the new short block and that he had got it from the same machine shop. I talked to the machine shop again and they said that the motor was balanced but they couldn't find the records that said it was balanced with that flexplate or not. So what will happen to my motor if I install this weighted flexplate instead of a neutral balance flexplate? Will it cause any damage?