On the Faber-Castell facebook page, I made an inquiry about the date of these pencils. This was their response:
We are sorry to inform you, that we aren’t able to date the Snow White pencils exactly. We didn’t find any proof in our catalogues. We can only assume, that the Snow White pencils were produced in the 1980’s. In that time several fancy pencils in blister packs were offered as retail products. For example Faber-Castell “Mickey” pencils were in the market and the 50th jubilee of Walt Disney’s film “Snow White and the Seven Dwarfs” (1937) was celebrated.
Then I heard from collector Michael Filippello. He owns a sealed pack of 14 that he purchased while still in high school. This dates them to the early 80s--circa 1983.
Special thanks to Michael for sharing his images and info on these hard-to-find pencils.