They are marked as Usart on datasheet.
Yes they are the pins for the USART, when you use serial data you are using a UART
UART ( Universal Asyncronous Receiver Transmitter )
USART (Universal Syncronous Asyncronous Receiver Transmitter )
The sort of serial data you use talking with computers, downloading code is an asyncronous code. This means that each byte is synchronised with a start bit at the beginning and a stop bit at the end.
With synchronous data no such information is sent and the data must be synchronised an other way, like transmitting a clock or framing packets of data with special patterns.