Source: The Wrestling Observer Newsletter
Here is the latest on El Generico's WWE gimmick. While he did make his NXT debut under the El Generico ring name and gimmick, there is no guarantee that he will keep the gimmick. It is usually WWE policy to own the names of its superstars and they do not generally allow its talent to bring in established names/gimmicks.
At this time, it seems very likely that Generico will be getting a new gimmick before he makes his TV debut.