The packs are manufactured in china, yes. I don't recall seeing any kind of brand names on the cells inside packs I have dissasembled. Usually just a capacity sticker and some serial numbers.
HK, in china, then brands them with various names, Zippy, Turnigy, Nano, etc. They must be relatively inexpensive cells, or they'd cost more. The very least expensive types do have a somewhat more spotty QC track record, but even the higher priced nanos can still have questionable QC.
SOP is to buy about 10% more than you need, because in a large order it's nearly inevitable that some packs will not perform perfectly. Get em shipped from the closest warehouse to you, so you can return bad ones easier, if possible at all.
I look at it this way, 10% more at these prices is not so bad. Generally the bad cells are assumed to have been contaminated when manufactured, causing cells to puff or fail to hold a charge. Sometimes they get damaged in shipping, which is why I advise getting them shipped from as close as possible to your house.
It's up to you to quality test your packs, so that when you assemble them into a battery you know it's free of defect packs.