97 SL320 is correct. You want your wheels to be dynamic balanced. That requires an inner and outer weight. Usually the inner is a lip clipped weight and outer is a sticky mounted inside the barrel as far out as possible. This way is very standard practice. I have balanced TONS of wheels, and we usually had to do it on aftermarket wheels or OE wheels that were lipless on the front face. In the latter, we had no choice.
It is very important that the rim barrel be very clean where the stick weight goes. At my shop, we used a rag with solvent and spot cleaned it. We never charged extra though, that is just preposterous! Once they're stuck on, they won't come back off easily.
Once you refinish the rims, if you include repairing the outside lips in the process, using sticky weights from then on will prevent any lip damage from a crappy balancing tech. Of course, you still gotta keep an eye on those street curbs too!
Hahaha!