I used to run a tire shop. I have balanced probably 10,000 wheels and tires. Assuming that tire is actually balanced (which you can't tell from a picture) there's nothing wrong with what they did. There are weights on the inside and outside of the wheel's centerline -- they're all behind the face of the wheel, because with most alloy rims you have to use stick on weights, they're ugly, so the outside ones go inside, but as far outside as possible. Not being able to put them at the edge means you need a bit more weight, and they could have used heavier stickers (but they probably didn't have them, we always ran out). If the tire isn't balanced, then they screwed up. But that's true no matter how many or few weights they used.
If I liked the customer, and wasn't terribly busy, I might have rotated the tire relative to the rim. That can change the balance weights required. Probably not for a used tire that was going to be a spare, though.