T4 : Prequel, sequel or equal?

(There is no spoiler here, just hints)

...what's up with the cameos. There were 2 old actors and you guess it right if you are thinking about that guy who has not acted for quite some times as he changed his career. I was not even sure whether that was him or just some digital feature of him.

Then there was the song from T2. If you remember the first time you see the late Edward Furlong in T2 (and yes, he's dead) then you remember that song by THAT defunct band (with the original members but came out with new material just last year).

Then, for the first time, I did not know that places can also be a cameo. Or was there 2 places being used again? Your guess is as good as mine. 

I did not give any part of the storyline away right? Just go watch it yourself...

The T4 poster at the cinema

But, before I fade away and try to seem to give the game away, let me ask you this (which was asked before by some columnist in a newspaper, which I can't remember when or where) :

If this story is about John Connor and he met his father who was then sent to 1984 who impregnate his mother while saving her from the Terminator, what is T4, is it a sequel or a prequel? I mean, it has to come first before events in T1 happens. And then, should this be T1, then T1 becomes T2 et cetera, et cetera?

To me, it was too confusing to be thought of and it was a good movie, but still I am waiting for that movie that I want to watch again and again, which I have to say Star Trek is a good bet. For now...

And you better revise back all those Terminator movies here