I don't think this has been documented before, so I thought I would share.

If you want to install an NB power steering pump on an NA, you can—but you’ll need to swap the brackets and the hydraulic fittings from the NA pump. You may also need to shave about 0.5 mm where the bracket meets the power steering bracket on the block.

This also shows that if you want to make your own AN high-pressure lines, you can use an NB fitting and attach it to your NA pump.

 

I did this for a while, NB pump with a NA rack and NA high-pressure line. NB pump's high pressure valve works with the NA line fitting. I found that very quick steering inputs, like slalom or avoiding pot holes, would "out-run" the pump and you'd experience momentary lack of steering assist. Didn't notice it on track though, wider turns means steering speed wasn't high enough I guess. It did noticeably reduce assist though to a happy medium, NA6 PS users might like it. The NB pump is also a lot cheaper than the late-NA equivalent.