50g - Differences in production batches

[rprosperi]

I'll just point out here that leaving the question open as to whether or not any blue units had s/n stickers, it likely would have gone unanswered. Boldly claiming there are none yielded near-immediate proof to the contrary.

It takes a while to learn how to manage the crowd here...

As for Massimo's s/n, I'm surprised to see a blue 50g from 2010, I thought they were from 2013-14 or so. Live and learn...