I agree a mass of the ball bearings are probably made in China but there are still many companies in the US, Japan and Europe making precision products wanting top quality ball bearings. European & Japanese CNC's and car manufacturers use high end bearings not the crap from china. At the end of the day a pinball bearing is selected from a range of bearing available and doubt a custom made ball. A while back I investigated getting a US bearing company to make a bearing and then specially ceramic treat it for lasting shine and achieve different colours but didn't proceed due to the minimum order size.

http://www.americanbearings.org/?page=memberlisting

So it is possible that Pinball Life is using American Made bearings

But given Mike is overseeing the process and specifying the material type and finish then I think they will be just as good as any high quality bearings as it comes down to quality control and Chinese bearings are known for their inconsistent sizes and impurities.

Out of interest Mike what is the material used for you premiums and pearls?