100% yorkies comes in all shapes/sizes.
So even if your Teddy might grow up to look little different from the standard yorkies you're used to seeing, it doesn't mean he's not a "real" yorkie. I don't think it'll really matter in the end though. You'll love him regardless.
With that said, just from looking at the picture... Something about his face that makes me think he might have something else in him... Perhaps others can identify better.
He seems very sweet and loving!