No. From his own writings…John Gordon picked these from populations of seedlings he grew out. ‘SAA’ meant 'Saved As “A”(meaning #1/the best), 'Saved as ‘‘B’’. ‘Saved as ‘C’’. etc.
So… SAA Overleese was his pick as the best Overleese seedling, SAA Zimmerman was his pick as the best seedling of Zimmerman, etc.
Because of the issue that many folks have encountered with grafts declining and dying off, JHG opined…no later than the early 1990s… that if he were 30 years younger and starting over, that, rather than planting grafted pawpaws, he’d plant seeds of named varieties and select those seedlings with largest leaves for outplanting.