SN65DP159: SN65DP159 Data/CLK-OUT Pin internal structure

I would like to ask a question about internal construction of the following pins.

- OUT_Dxp / OUT_Dxn, OUT_CLKp, OUT_CLKn

Are there any ESD protection devices internally on these pins? 

Currently, I am not using the external ESD protection devices for these pins.

I think that it might be better to use external ESD protection device to avoid for ESD issue if SN65DP159 does not have internal ESD protection devices .

Best regards,