Given that I have some orange-label mono LP's pressed c.1969 with stampers dating back to the early 1960's, somehow I'm not surprised. But here are some labels with this very variant of Nipper and the gramophone for comparison: 1965-68 LP label 1965-68 45 label
Must've used older stampers, then. But I saw your linked examples, and those were definitely pressed in the '50's. This has all the markings of a 1965-66 pressing, based on the dog. Also, the type of paper used might be a tad different from those '50's copies.
It isn't just post-1954; I'll go further and date these labels to 1965 or '66(!). The dog looks exactly as on 1965-68 "black label, white lettering, dog on top" LP labels - and on 1965-68 "black label, dog on side" 45 labels. Some of these "educational" pressings even had newer rim print that eliminated the reference to Camden, N. J. That you mention these as being pressed on vinyl cinches it. Tell me, is there a concentric locked groove on each side preceded by a turn or so of 32 pitch catch groove that comes after the 4 pitch lead-out, as would be indicative of post-fall 1964 lacquer cuttings by RCA studios in New York?
These 4 disks are a part of an unknown album set (catalogue number E 88). It is not known if there are more disks in the set. The first part of the matrix numbers, E1EB, indicate as follows: E1: 1951; E: Educational; B: 10 inch - 78 RPM - Standard. However the colour dog label design indicates a post 1954 pressing as the colour dog label was not in use in 1951. They are pressed on vinyl and not shellac.