It is possible, maybe they are close friends or siblings. A good case for the latter is the mangaka Seishi Kishimoto (666 Satan), twin brother of mangaka Masashi Kishimoto (Naruto). They have similar drawing styles, so they are frequently accused of copying each other.
It really doesn't help that m1's name could be misinterpreted as mouse1 shorthand. The first version looks alot like mouse1, but the final is unmistakably M1. post #4762 is a good reference.