Power Steering for a 71 C10

[TONY2000]

Hi just picked up a C10 1971. I need to clarify a couple of issues.
Its a 1971 according to vin no: CS141B63148 with a 307ci Turbo 350 box.
But has a small rear window, No power steering and drums all round, step side body.

The Guy i got it from said its a 67 Because of the small rear window ?
Also said the 307 V8 was original, Vin conflicts by saying 6 cylnder.
Im sure Vin no is correct but wondered if the small cab window was available on a 71 ?

Also im trying to source a Power steering set up but need to be sure which ones fit etc.
Im trying to find a supplier of a complete bolt on kit for my truck.
a couple of company's i've e-mailed don't list one for a 71 !
Also going to change to Disc brakes, again 2 company's local only list a Disc Kit for 72 onward's ?
Any help would be appreciated.

Oh and i'm in Australia so i need to be sure before i ship one out to OZ.