At this moment most, if not all, device manufacturers don't distribute OEM parts for the repair community, so in most cases they are not 100% OEM. In our industry various terms are used to differentiate quality and price differences, what we are trying to do with the OEM moniker is make is easy for you as the consumer to differentiate what everyone means.
That being said, our OEM parts are the closest you will get to the real thing. They are manufactured using either actual OEM parts or using OEM grade parts (such as the glass.) In other cases sometimes the parts being offered as OEM are pulled from existing devices or are OEM grade products which were available in the global supply chain.
Because the availability of parts like these are limited, price can be higher, but you can trust they are the best parts in the business.