As someone who has been a golf sales rep for domestic and foreign brands I can tell you that the clubs have to be knock-offs or counterfeit. The prices are even below the prices that one could get with an employee purchase when being a sales associate at a major golf retailer like golf galaxy or dicks. The prices are even below what the companies sell their closeouts for to a retailer like dicks or golf galaxy. Markups range anywhere from 30-50% on golf clubs, and then employees typically get another 10-20% off of those prices when they fill out the appropriate employee purchase paperwork and buy directly from the company. the companies have strict policies against the sales associates then taking the merchandise and selling it to a consumer, if caught that employee can no longer employee purchase and sometimes it is mandated that the retailer terminate the employment of that individual.
Now, many golf companies have their clubs manufactured overseas. Most of the clubs are made there as is every components of the club (shaft, head, grip). Some companies advertise assembled in the usa, but only a small amount of their product offering is actually assembled in the USA. Most of the merchandise is entirely made and assembled in the area of which the clubs are manufactured. The companies are hired to make x amount of each model. As always, there are going to be some flaws, but the company will not buy the flawed merchandise and the manufacturer has no need for the flawed merchandise. Often the manufacturer will sell the flawed merchandise to a trade company or even consumer direct. So in the best case scenario, while still rare, anyone who bought these would be getting factory seconds.