I don't doubt it's done but I'm not sure how many look at past results to seed a bracket. I certainly wouldn't as it would take a lot of time to gather and digest that info to make it meaningful. I do know some just learn who the top kids are at certain weights from being around them. If there are a clear top 2 kids, seed those and the rest are drawn in.

I've heard requests several times to have a kid on the same side, opposite side and most often bracketed with (In RR brackets) certain kids seeking out best matches. It's up to the tournament directors to do something with that information if they choose to do so.