Yup... but you can use 15A receptacles on a 20A circuit, there just needs to be more than one. If there is only one receptacle it needs to be 20A.
And a single 15amp
duplex receptacle qualifies as more than one...
I find it easier to just use 15A receptacles. It's pretty rare (if ever) you run into components with a 20A plug that requires a 20A circuit. ...
Yup.