I don't think you can discount it based on the logo.
http://www.sportslogos.net/logos/lis...ncinnati_Reds/
It more closely resembles the logo from '20-'35 and '37-'38 than it does the later logos. The only difference is that "REDS" does not extend such that the "S" is in the opening of the large "C". In the later years, the logo has a reverse coloring scheme from the logo in the postcard.
Real or fantasy piece? Sorry, but I can't help you.