That's exactly how it happened for me, though I had been riding a moped for several years back when you didn't need a license at all - just had to register them and get a plate.
Actually, since I was one of the very first people to go through the process of upgrading this grandfathered ML to an M, the Ministry staff had a nightmare trying to figure out how to make the system remove the L restriction. After I passed my regular M2, I eventually had to go to the downtown MTO head office five times and wound up speaking to the general manager twice. I think I got about three copies of an M2L license card before it was sorted.
