Their newer top of the line, the Super Slams, are made in Japan. I don't know about the Grand Slams.
Natchezss, almost the go to place for Weaver these days because they buy entire production runs just for themselves, will tell you what is printed on the box if you ask. I think the Super Slams are excellent and compete with higher dollar scopes optically and in turret quality, but are very heavy as well.