Power steering pump cap and painting

[440ehigh]

Im trying to figure out the correct cap for a Saginaw power steering pump. In the parts book they list a part number for the 70 year and a different number for the 71 year. I'm pretty sure the 70 part number is for the vented cap with a hole in the center. Then I'm wondering is the 71 part number the non vented cap or what's the difference between the part number caps. If the difference is vented cap vs non vented cap. Was the change due to the 71 emission requirements that happened that year. So it couldn't be a part that was carried over till stock was used up like most parts.

Then I'm getting ready to paint my pump and brackets. I'm wondering if the 3 bolts for the front bracket and the 2 nuts for the rear bracket are attached after everything was painted. So the fasteners would have the phosphate finish. Or would they have been attached and dipped painted all at once. Same with the nut for the pulley would it be painted black or phosphate finish.

I plan on using the reproduction power steering pressure hose. What's the biggest difference to the original just looking at pictures it looks like the finish and part numbers stamped in it.