@Kaarme I see your point.
However, the was I see it is twofold. Firstly, I find it less about the act itself, and more the ease with which he decides to go through with the experiment: He could have shown a little more hesitation to appear more "good" (according to commonly accepted values).
Secondly, I see it less as turning iron into silver, and more as turning $5 bills into $50 bills (or some numerically equal equivalent), which
would be considered a crime, even through the use of modern science.
Considering he never does it again (at least on camera), I can accept that it was along the lines of "easily misunderstood experiment" rather than "deliberate act of forgery," and that the character isn't inherently trending towards "evil."
In terms of your second point, I can agree wholeheartedly about the comments on the classic alignments. Most people have a skewed idea about what the alignments are, and quantifying morality is a can of worms that my TRPG group has all but abandoned: I personally believe that morality (and, thus, good and evil) are subjective.