Yes, the EMJ is one of MANY ways the 145 is referred to by Envoy. Depends which section is referring to it. It can be very confusing without the context of know what the OTHER plane is referred to by that particular group. The 175 has just as many names as well, by the same groups, but generally PILOT documents refer to the 145 as EMJ and 175 as ERJ, which is what the type rating shows.

Embraer actually refers to the 145 as the ERJ145 and the 175 as just the E175.