Here is one example of how Schleich does this now.
Could be interesting for some collectors.
Here you see that all parts and accessories cavitynumbers and clock- date-markings. Both these markings are so that Schleich can see if anything is wrong in their cavities in the molds and then also when it was made. Therefore these markings are on all pieces. So if a smurf is made out of 2 or 3 pieces then all the pieces have these markings.
But the addressmarking is a regulation for toys and Schleich only need to have that on one piece. So in this case with the computer, the addressmarking is only on the computerbase and not on the other pieces.
Here is what Schleich told us in another thread: "Thanks to new laws in the US (I believe it is ASTM F963 or CPSIA or so..) the manufacturer of toys has to ensure that he can document all production steps and materials used. This should be relevant for all toy manufacturers, but as Schleich wants to be part of elite of toy manufacturers, they take safety issues especially important. The law started in August 2009, but it still seems uncertain what exactly the manufacturers are required to do." And this "The supersmurfs will have markings, too. The idea is that for example if a customer sends in a broken part, Schleich will be able to identify which material batch was being used and when the part was being produced (and on which machine). But Schleich policy is not yet 100% clear, so you might not find the marking on every single piece on a supersmurf.. "
Another intersting thing is that the clockmarking is part of the mold and therefore will be on the same place all the time. It is only the inner part of the marking they change depending on when it was made and which year. Schleich: "The marking is part of the mold,
The inner part of the date stamp has to be renewed every year.
Maureen 
