Did the Apple ][ ever ship with an autostart ROM from the factory or were they all the older ROM with Trace/Step?
My guess would be that once the ][+ started shipping then new Apple ][ production (well at least once the non-autostart ROMs ran out) would have an autostart ROM but I can't find anything to confirm this.
Just to add Jim Sather in https://archive.org/details/understanding_the_apple_ii says that his rev 3 board came with a non-autostart ROM. (Thanks to @blrfl for making me check this)