Rear wheel weights fell off

I just got my new tire mounted and balanced and ended up cleaning the chain too. I didn't notice till after cleaned the rim that two wheel weights had fallen off and I can't find any residue to figure out where they used to be. My bike did have a clip on weight beforehand and read somewhere that weights are usually all put in the same place is this safe to assume? Dont really wana remove the tire to get it rebalanced again, any suggestions?