Usually all production figures will have some kind of markings, sometimes the plastic that is injected into the mould doesn't fill the cavity properly and can fail to pick up some of the minor details like the COO (even so you should be able to see some remnants of the markings) but yours looks like it was made using a mould that had no COO/copyright info present, every detail on the legs looks just fine to me.
I highly doubt this is a pre production figure but it is worth noting that the reason first shot figures usually have no dates (although there are exceptions) is because they are the first figures run through the fresh moulds - the copyright/COO is then added once the figures that come out are approved for production.
Could you send me some high resolution pictures to my email? It's in my signature - I can speak to Wolff to ask about this figure and also to Bill who knows a thing or two about Vaders