Your bolt carrier should not be anything like a charcoal briquette. Lol.
They are another small assembler of an upper from parts. If you don't want it and want to make a buck from the current climate sell it. If it shoots well and you want it keep it.
Mega is usually MMS. Their uppers have "Mega" on the side. Their forged lowers have checkering on the magwell front and their billet lowers have a toothed pattern on the magwell front.