Dating is an estimate from www.ausreprints.com.
Other printings of this story include: Totem (Aventures et Voyages, 1970 series) #26 (November 1976) [Original title: Le testament]
This is probably a reprint from the earlier title, The Lone Rider (Ajax; Farrell, 1951 series)
This item is a K. G. Murray house advertisement, based on the back cover of 100-Page Super Spectacular DC-15. Part of the "A" symbol on Aquaman's belt has been left on the figure that has been converted to Superboy, even though other elements of the constume have been drawn in correctly.