I don't think so. The EXTMicroUSB is a longer plug, but the only time it would have more pins in it is if it is an MHL adapter.
The two are not the same thing but you can have both in the same plug.
However on the Rezound, if you are using an EXTMicroUSB, it will have a snap in feel when you plug it in and not easily fall out like regular MicroUSB plugs do with it.
I don't think you will get better anything using a different MHL adapter from what you are already getting.
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