Not in these cases. The plants are going to be sent in sealed containers which themselves will be free of external contamination. Barring physical damage like a

Not in these cases. The plants are going to be sent in sealed containers which themselves will be free of external contamination. Barring physical damage like a meteor impact or a crashed lander, the chance of "contaminating" the moon is slim to none. Even then, the conditions on the moon are such that organisms will either die or go completely dormant in the low-temperature, oxygen-free environment.