The cardback still bears no indication Strobo was meant as part of POG line.
In a panel at Grayskull-Con, Emiliano actually talked about Strobo being part of the figures Mattel were making with lot of re-used parts. Examples already being Ninjor, Randor, etc at the end of the line before they were preparing for POG. So Strobo would have been at the tail-end of those figures before POG.
Also interviews from past with creators mention that Powers of Grayskull had big plans as a spin-off. Nothing about making it cheap. (He-Ro and Eldor figures don't seem like re-used figs)