No - and not only that, but for future reference, you cannot safely re-use cables between two different modular PSUs either.

The ends that plug into devices like the motherboard are standardized, the ends that plug into the PSU aren't.

it does matter. the 20+4 side goes into the motherboard

It looks like the 24 pin slot on the PSU has two connector locks (the small piece that clips onto the motherboard), one centered over the 20 and one centered over the 4 pins.

Having just gone through troubleshooting a modular Super Flower and mapping the pinout myself — yes it absolutely can matter. The pinout from the PSU side doesn’t necessarily follow the pinout at the motherboard side.

Thanks for the reply! If this is the case, would you happen to know which end of the cable I should hook up to the motherboard and which end I should hook up to the PSU?

The plugs casing should be designed to only allow being plugged in a certain way. The pin outs will follow this pattern appropriately. So technically it would not matter. However, if your MB is a 24 pin and your PSU is a 20 pin then you are not going to be able to provide power to certain parts of your MB. It is perfectly ok though to plug a 24 pin connector into a 20 pin MB as the additional 4 from the PSU side just wouldnt be used.