Polarity Thermocouple

Polarity Thermocouple

Bought the Raise3d Pro2 Upgrade Bundle.
Manual says the K thermocoupler wires is color coded. The wires on the ones that came with the kit is all black.
How to figure out the polarity, or maybe it doesn't matter?

Manual says:
The Type K Thermocouple follows the ANSI United States color code, where yellow is positive and red is negative.