The OEM stands for Original Equipment Manufacturer, that’s a factory. In some instances the OEM owns the distributor, in some countries that OEM has created or is affiliated with a specific brand that they sell their products under or through.

The manufacturer is encoded in the VIN with the first three characters as an identifier. It is the only way to see the actual OEM.

Zongshen sells engines and so do others, if a second manufacturer buys engines from the Zongshen then only the Engine has the OEM as Zongshen. The rest is theirs if they are assemblers, they become the OEM.

There are lots of assemblers, they buy components from many sources, there are centers for all parts, engines, frames, everything…..

EASTWORLD MOTOR INDUSTRIES CORPORATION is Motorstar they assemble in the Philippines and yeah they look to be connected to Zongshen, most of what they sell is a Zongshen model, bet that Zongshen is selling CKD units to certain enterprises, they also do that with Corven and it looks like Motorstar is another.
http://www.corvenmotos.com/

But that is only an affiliation, unless Zongshen owns a share in the actual enterprise, like they do with Kasinski and Ryuka.