Sorry for reposting a coin, but I was looking on http://numismatics.org/crro/ for examples of coins of the same type as mine and found one from the National Library of France that I think could be a double die match. What do you guys think? If it is a die match, how common is it for coins of this time period? Would it provide some evidence for the authenticity of my coin? (my coin is the one on the bottom)
Andrew, Despite being so far off center & striking weakness on the reverse, it looks like a double die match to me . Nice detective work .
It's kind of hard to tell because (at least on my screen) the top image is so dark. But the obverse, at least, looks like a match. There's nothing unusual about finding a die match for a Roman Republican coin, whether single or double.