that is not a beercan, the beer can is a steady F4
it will not have any dash after the F number
that other one is just a standard lens
i would suggest holding out for the real thing as they are supurb for the money, and even compared to much higher priced lenses
There is a reason that even though i have migrated to primarily G lenses, I will always keep my beercan family (24-50 F4, 35-70 F4, and 70-210 F4) and that is they are great lenses, maybe not as fast as others but very sharp, good bokeh, Built like tanks, and fantastic color.