My wife works in the textile industry, a major concern of brands is exactly what 7seas stated.
A factory is contracted to produce 1000 widgets. Unless your dealing with very high end designer labels, the factory in many cases also sources the materials. So if said factory produced 1200, 200 over the contracted amount, they then release the 200 themselves. Usually it is to the local market as knock-offs despite being very much the real thing despite not being authorized by the brand. In the case of something like a prop, eBay is the most logical outlet.
Top designers that produce overseas will send the materials to the factory to try eliminating this practice. They also pay well enough to discourage the factories need to offset income.
While this may not be true and what we know of MR’s final days does suggest it is as DigiGal has posited, if we see other MR product surface…