Somebody has a 1957 Western Round-Up test wrapper listed on eBay right now which I haven't seen previously. The description includes the following text:
"Very rare find. This paper wrapper was used and covered a pack sold in candy stores in 1957. A test issue that was very limited to start, and I wouldn't think there's more than a handful in existence now. The wrapper would be high grade but for a tear that extends from the middle left border to the fold line. The tape you see has nothing to do with the tear and was issued this way to close the pack. Therefore, on the corresponding side right border also has a tiny spot of paper loss. All of these paper issue packs have this because they were issued with the tape. Other than that tear, it's in nice shape."
I just remembered another one! But this one is from 1969, not the 1950's. Probably because it is oversized and not a standard wrapper. Topps Pak O' Fun.
Paper test wrapper, closed with tape...
Retail wax wrapper...
Not only does the test wrapper lack the full background, look closely at the card artwork surrounding the title and the price... different coloring.
I'm still searching for others...