These are not "very early" seals. Dennison's packaging became quite plain and much cheaper to produce during the 1950s. Out went the slide boxes and in came these minimally decorated envelopes with the silver back seals. This set is from the later 1950s and into the early 1960s. They have a value that in no way approaches what this seller has as a BIN price.
Mark B. Ledenbach's vintage Halloween collectibles blog.