While not an "expert" on AAR/TA, I read that service bulletin. 71 340 cars with fast ratio steering would get the same pump used on 70 fast ratio cars, i.e. aar.
Says nothing about a special version of pump with fast ratio.
Not all 340 cars got fast ratio, and all the ones that were power steering that I've seen had a Saginaw.
I've only seen Saginaw on C bodies with the 360, in fact have 2 to look at.
The fact that the pump was used on 340,360,383 and 440 in 69, 70,71 doesn't mean they were used on all models and all engines that could fit one. So application chart just covers over all use of pump.
So going back to my other original question of did they make different flow and how to i.d.?
I see incorrect Saginaw selling on Ebay for much. Classic industries has a repop, needing pully and brackets.
I could get pictures, but it's the federal 340 pump.