Will customs confere a slingshot if bought from overseas?

YES..Though primitive they are considered a "weapon" and are on the No No list of things you can't have coming thru customs. If I may suggest an easy solution, just ship it UPS or Fed Ex or the Post office from your oversea's location.Perfectly legal to ship. No hles or airline issues and it will arrive here in the U.S. timely. Hope this is a solution you can live with!