I want to make a quick amendment - some VERY OLD piggies/glitters did have black base stickers (my lust dust is an example), but we are talking old, old - not new, and all of the of the black base stickers I have ever seen have STAMPED batch codes. Now, the dot matrix print on the bottom of that jar of Tan reminded me of an earlier post - - see this example pic courtesy of eowyn797 - this is a jar of Red matte d'cd which the owner queried authenticity of - it not only has dot matrix coding on the base of the jar similar to the tan but also the base sticker (even thoug it is clear) was not printed with a batch number similar to the tan. The red dot code is like newer 3 digit codes, but the tan has a 5 digit code not disimilar to the old 5 digit coding on very early MAC products.
maybe the tan is just a super old pigment - specktrettes what do you think???