strut rod bushings?

OK, been getting some great advice as I rebuild the front end of my 70 Duster, so am throwing out another question. Hopefully this will be the last one. I got the performance kit from PST. The bushing set they included for the front of the strut rod is different that what I took off the car. They were pretty confident they were correct. Attached is a diagram of what they sent for instructions. Mine did not have the spacer, centering collar or the washer toward the rear of the car. I want to verify that is what my Duster is supposed to have, from the size of the hole in the frame I would think it should but it doesn't show in the service manual picture. PST included the spacer and I have the forward washer. Can I just use a plain flat washer for the rear as the new bushing has about an inch or so flat end instead of the concave washer? And also does anyone know where to get the centering collar?
Thanks