If there is 1 receptacle on the whole circuit (i.e. one SOCKET not one yoke), then the socket must exactly match the ampacity of the breaker. (noting that 40A sockets don't exist; for 40A you use 50A sockets).
For 20A circuits, if there is more than 1 receptacle on the whole circuit, then 15A socket(s) are allowed, as a special exception to let you do exactly what you want to do
The upshot of this is you only need to carry duplex 5-15's on your truck
For 20A circuits, if there is more than 1 receptacle on the whole circuit, then 15A socket(s) are allowed, as a special exception to let you do exactly what you want to do
The upshot of this is you only need to carry duplex 5-15's on your truck
