Hi KevinH,
Sorry, it’s hard to describe in text!
a) there is no visible indentation.
b) yes, it is completely smooth.
The decoration isn’t just on the surface so it isn’t simple combed decoration as shown in the YouTube clip above. If you took a section horizontally through the weight, it would look like a wheel with five spokes with a hole in the middle. For each section, the decoration goes around the outside of the wheel, then down the spokes to the hole in the middle, which is the bubble.