This listing tells an interesting tale. When Gibson first began producing boxed goods like Dennison was doing, they were scrambling to catch up with their better capitalized competitor. My theory is that they rushed to market with designs bought from German artists, stamped with their Gibson mark on the reverse and hurriedly placed in boxes, so hurriedly that there was no indication on the boxes of the expected quantity per box. I've come to the conclusion that these early Gibson slide boxes were made in the teens, probably closer to 1910 than to 1920. (My book shows this box on page 222. I'll add the new production dates in the errata.) In every instance where populated early Gibson sliders have surfaced, the seals contained within are an assortment. (Not as wide as this assortment, as this includes some seals that weren't made by Gibson.) Relative to this lot, the box and most of the seals are definitely worth having.
04/29 Update: Someone really felt this was worth having as it was bid up to an eye-popping $197.38.