In a couple spots I know they are. In others there's foresight that the founders simply wouldn't have had. In some the tone is clearly 2 year business student etc... they are not real pitch decks. I've seen more than my share of real ones to know the difference.

Sorry man... I'm sure you have good reasons to question the validity of some of them and I don't doubt your sincerity. It was my understanding that they are all legitimate. I don't want to promote a 2nd year business student's work as an original pitch deck so I can look more closely into the provenance of problem slides if you could name these and I'll either redact them or adjust the title accordingly. Thanks for bringing this up :)

I just want to add my 2 cents in hope that it's helpful. I'm a co-founder/partner of a seed-stage VC fund and do keep track of the pitch decks we've seen as a partnership over the past two funds spanning six years.

Comparing these decks to the decks I have in our tracker (a dataset of similar size to yours), there's a lot of differences. Even if you only take the pitch decks of the successful companies (most of which we didn't invest in), a lot of these decks look a lot more polished.

Here's what I think is going on: Some decks are undoubtably real seed pitch decks, some decks are demo day decks from accelerators, and a few of these decks (Facebook's, for example) are after-the-fact business school exercises from students.

So, I do think most decks are real, but what's tripping up some people is how polished some of the decks are. True pitch decks used to get a seed round or into an accelerator aren't very polished because you're constantly changing the deck based on feedback over the span of 20-50 pitches. The truth is that many investors I know worry when they see a too-polished deck that everyone else has already seen the deal and passed :-P.

You don't think TheFacebook orignal pitch deck was called "Facebook's Original Pitch Deck" ? /s