Modelo is the brand, negra is the type of beer. It's negra made by Modelo -- Negra HECHO POR Modelo.
Doesn't really have the same flow to it. It's proper Spanish the way they have it.
it'd fly if it were from some english-speaking country where gender doesn't exist in nouns and adjectives. however, the context is ambiguous as all hell in this example since spanish features gender-specific nouns and adjectives.