I always felt that this was a rather flimsy premise, but can we conclude whether this has indeed worked either way? As ridiculous as it may sound, have Asian carriers warmed up to the 787-8 more so than if it had been a good old 787-100? How about the 747-8i? The A380 versus an 'A360'?
I guess the A350-800 and the A330-800neo can be excused because the manufacturer lost interest in the former after the stretched versions rendered it as the modern version of the A342, and the A330-800neo is still in early days of its sales cycle.
Good thing Boeing had the 787-'3' in the works, otherwise the 787-8 would've been shelved in favour of the 787-9, -10 and -11. The irony though? The -3 was plugged exclusively around Japan IIRC.

In essence, I find it hard to believe that multi-billion dollar businesses work in such a fashion that they can be easily swayed by - in this case - a 'lucky digit' here or there. And since they aren't, why did A/B go down this path in the first place? Nothing to lose or did they genuinely have a hunch about something?