That video has long been my favorite piece of Japanese humour, ever...
Indeed, as someone else pointed out, you must have attempted a nested spoof when asking whether this could really be a spoof.
Most of the stuff should be fairly obvious dry humour to everybody, non-japanophiles included (exact angle measurement in degrees of how your hand should touch the noren, or how many CC's of shoyu is to be poured...)
For those who have lived a bit in Japan, though, the whole thing from start to finish makes a hilarious spoof. For the sake of those who may have missed some of the more "obscure" points (I don't think the video was ever meant to be viewed by a western audience originally):
1) "oh toh toh toh", "mah ma ma ma" is only uttered in particularly backwater places or by geezers old enough to remember the days before electricity. Say that in a sushi-ya once (especially as a foreigner) and you'll get looks ranging from incredulous to hilarious.
2) 雑巾 (zoukin: duscloth) is most definitely not how you call the ubiquitous white towels people use to clean their hands (おしぼり/oshibori)...
3) Need I say it: the famous "honne" and "tatemae" concepts of what you say and what you think (in a rough), have little to do with the idea of delegating responsibility for the evil deed of eating protecting species on the cook or blame it on their ignorance of the situation. On the other hand, Japanese have been known to refuse to give up their whale meat snacks despite their status as an endangered species.
4) The salt you can find outside of most restaurants is meant to keep spirits out, adding it to the end of your meal would be the Japanese equivalent of washing your hands in a baptismal font.
5) Also: the insistence on explaining everything as a direct result of Samurai culture (「なるほどう、侍の国ですね」= "Indeed, this is a country of samurais") or as a complete mystery (「謎です」) are cheeky references to the ever popular Nihonjiron ("specificities of Japanese culture") answer to about any question.
This, only to go after the less obvious cultural points of the video, as for the rest, I don't think there is more than a two or three pieces of accurate information in the whole documentary...