A:Answer Yes, I bought an S3 dock, and plugged it in, put my S2 watch, and charged like a charm. Buy with confidence!
See attached picture, red light means charging, and I've used it to charge the watch from 4% to 100%
You can see the watch is an S2, and the dock is an S3 (quite bigger than the original compared to the size of the watch
Hope this helps!