I literally just now got my wife's new size regular Neo-Air via UPS and — of course — the first thing I did was to weigh it. I get the weight at 409 grams (no carrying sack and without the included documentation) — wonderfully close to the 410 grams listed on the box. Even better, a recent check of my scale using shiny new coins suggests that it reads about 1.6% high, so the true weight might be even a bit lower, 402 – 403 grams perhaps.
Of course, marketeers being the creatures they are, the listed 410 grams converts to 14.46 oz, which I guess they justify as rounding down to list at a simple "14 oz" with no decimal point. But in the 402 – 403 gram range, that's about 14.2 oz — not bad at all.
Now I'll inflate it for the first time and see just how loud this crinkly noise is that I've been reading about! :-)
Note that the weight also doesn't include any sort of patch kit; I guess I'll just scavange the patch kit from the inflatable I was using, but apart from the cheapness of not including this with an expensive mattress, it also increases the true weight for those that are inclined to carry one. I expect I'll just use a gallon-sized ziplock bag as a carrying case (13 grams), and with that plus even a pretty minimal patch kit, the true weight will be a bit more than 14 oz. Still — pretty good!