Yea you got some really nice early imports from china, back in the day that the word import still kinda meant something good and with lots of folk style to them. Some of those bowls look pretty cool though. Though you see many brass bowls that are import in all the thrift shops and rummage sale, mostly with India, then Japan. That might help you get a few pennies, all in all I can pick them up for under 5 bucks, not sure about Ebay, may have to go satisfy my curiousity after this, would bet there are a flood of them. I do think those cooler ones may be a bit better, but personnal I would say 5 to 10 bucks each after a few tries. Sorry I think any history would be extreamly hard to track, sure would say they look about 70+ years, don't look like the India stuff still flooding the market today