It is quite common that the different pins on the same port have similar VOL. But there will always be tolerances.

But some chips have individual pins that are radiacally different. For example the USB standard has electrical requirements that may force a processor vendor to make one or two signal lines different. And I2C requiers open-collector/open-drain which may make the I2C data pins different. Pins with combined analog/digital function may also behave a bit differently.

So you can never assume that multiple pins should behave in an identical way. The datasheet can tell if there is an important logical difference between them. And to that, you will have to accept that the datasheet only specify an interval for the relevant parameters and every single parameter for every single pin will have a random value somewhere within the specified interval, and this random value will not even be constant. It will be affected by temperature, supply voltage, ...

But as Andy notes: How do you know that all pins sinks identical (or at least almost identical) current?