I recently picked up an extra Classic Brainy 2.0536 and noticed that on his butt right next to his tail was a circular stamp. I looked at it under a loupe and it looks like a factory timestamp. We all know that some items have this code stamped into the plastic at the time it was made for quality control. You can tell which shift or time the item was made at the factory if there are any batch issues.
The question is "When did Smurfs start getting these?" My Brainy from a few years back (same mold) does not have this. I checked my old Classic Jokey and found it only on the newest one with the warning tag. This leads me to think this is a more recent marking.
I tried to snap a photo through my loupe to show the marking.
The next question is that will this make variation collectors go crazy?