Are we getting a PDF version that we can play around with of these rules?

Since the wargame rulebook will be a add-on, and then a retail release, I very much doubt you'll get a free PDF. Since, you know, that would keep some players from buying the hardcover book.

I do think it was supposed to be free as a PDF in the original KS information but... let's keep away from that.

Well I guess it depends, up to this point they had alle the rules as downloads (like the Warzone Rulebook and additional Rules stuff) but all without the Fluff.

So if there will be any background in the book exclusively to that I guess we will see the pure rules as pdf download ... if not ... well maybe we will still see the rules, as for today not many companies can get away with buy to read exclusive rules/content and still generate enough interes for their system (GW could/can do that and even they start to use the free download road)

Most people will switch to a free rulesystem if there is no pdf, and those how would have bought the book if there was no pdf will probably buy it anyway, just to have it and for the (usually) book exclusive Fluff.