There are a number of examples in the History of Steel catalogue (and the
on-line version), and they are discussed in the accompanying article as well.
I agree with VANDOO that the odds are not great that it is genuine, unless you can trace its provenance back at least a couple decades. I'm not sure when the repro industry really started taking off, but I'm guessing that during the Maoist era, and particularly during the Cultural Revolution (which ended in the '70s), they would not have been made at all, so it would have started later. Thus, anything that can't be traced back before the '80s is more likely a repro than not.