On the power steering reservoir you need to specify what you have as GM made a change and if you have the early style you need the early style to have everything fit like the lines etc....if you have the later style that is the better one....whatever you buy be sure it includes the cap as the cap is not interchangeable.
I have the 1987 style with the cap use din good shape. The 87 style has the embossed cap (raised lettering) the older style had a wider cap smooth top.