There are clearly two completely different marks, albeit in the same general position (although, not precisely) on the 1946 penny.
The one referred to as a footnote in Peck, page 518 of the 1964 edition, states: "Some specimens of this coin have a small raised dot (flaw) on the rev, high up after ONE (specimen in BM)'
Freeman, at point No 36 on page 75 of Bronze Coinage of GB book dated 1985, states "Some specimens have a small elongated raised dot in the field above the E of 'ONE', caused probably by damage to the die" - the operative word being "elongated" - thus highlighting the apostrophe shape.
The confusion seems to arise from the fact that the apostrophe shaped mark is referred to as a dot, the same as the actual dot penny shown by Bob, with the later excellent photo from Mick - but of course that dot is in a different place and is a different shape to the much more well known one referred to by Peck and Freeman.