Would it had mattered which two wires from a digital decoder was wired to whichever two wires from the digital power station?

I am making reversible modules so that mean at one time the two module would be connected red-red and black-black connectors but another time one of the module may be turned around and so the wires would end up as red-black and black-red instead unless the connector wires were manually crossed over. I just wanted to know if the polarity would matter (which in that case I would key the connectors to only fit one way then) or not (and so I don't need to key the connector but just connect them as I please)

Thanks from someone who has only ran analog trains so far.

You can connect digital decoders either ways.
They collect the digital signal from J or K (doesn't matter) and electricity is usually supplied throuh a rectifier.

In DCC, "J" and "K" are used to name red/black or left/right track.
For modules, I use two wires for the track and two extra wires for accessories (using a booster) to achieve full load on the track.

Regards,
Oliver

Thanks Oliver, and funny enough I had the same thought on separating the loads a bit like what you mentioned too.

As Oliver said, you can switch the wires if needed. Just make sure that you never cross the connections. This would result in a short circuit, when a train crosses the module borders. If you use Lenz ABC / Umelec for automatic stops, you can also run into trouble. If you want to use the feature to only stop in one direction, you are required to insert the ABC module on a certain track. If you turn your module at 180 ° the ABC module would be on the wrong side.

Best regards
Carsten