Wheel Balance Weights on 15" Wheels?

Where are the wheel weights on the 15 " wheels? I saw 3 new vehicles in the delivery mode, ie wheel covers not mounted, clear plastic over wheel to prevent rotors from rusting, and did not see a single wheel weight on any of the 12 wheels. So is there an adhesive weight inboard of the outward surface that normally gets the clip on weights?

I orginally thought one of the reasons for the plastic trim covers was to cover the wheel weights. But now I think it must be a brake cooling or fuel economy aerodynamics reason. I'm surprised that Toyota would add weight to parts that rotate at axle speed. This weight is so much more critical to vehicle performance than sprung non-rotating weight like carpeting.