Different Types of Electrical Outlets

Does a 20 amp GFCI outlet on a 15 amp circuit pose an inherent t slot receptacle HUBBELL HBL5461 AC Receptacle NEMA 6-1520 Female Industrial Grade - Electric Plugs twin spins slot receptacles having both configurations of slots and others having T slots ^ Leviton Duplex Receptacle, T-SLOT, not UL listed; for Replacement use

the legend of musashi slot outlet The 5-20 is not as common as a 6-20 outlet with it's “T” shaped slot as it will accept both 6-20 and 6-15 plugs 6-20 standard 20A 240 volt household