As JohnZ quite clearly pointed out, there have ALWAYS been 'good accurate RESTAMPS'... but they are still restamps. (The Corvette world and NCRS judging of 'high end' cars is a good place to check that out!)..
One should not look at ONLY the characters in the stamping to determine this, but analyze ALL aspects of the engine/car/stamping/etc to make a determination. IMO, having 'accurate stamps' is no more convincing as a single indicator than having a block with a good cast date!
note: Original broach marks are the best indicator I've found when all else appears good.