The answer to his question is "not necessarily". Stamps from famous makers do not mean the pickup from a cheap Asian factory is actually an expensive US pickup. How do I know? I bought no-name pickup on eBay that had the SD logo stamped on the bottom which was visible in the pic. It is possible that the baseplates were made in the same factory as ones for SD...but that was the only resemblance. The rest of the pickup was definitely not SD. I am guessing the same is true for bobbins. They might just buy their parts from the same place. Unless you know that the mfg makes pickups or other parts for a name-brand, this is a bad bet IMHO.