Can RX be used on read only pin?

[troy salt]

I'm having trouble understanding the pinout diagram. In the legend it says that light blue is for Serial pins. Pins 13-18 are read only but I don't see any blue boxes indicating serial. Not sure if that matters, so my question is can Pins 13-18 be used as RX for serial?

Thanks,
The salty one

[robert-hh]

@troy-salt Yes.