I sat down to post a variation on this same question and saw this thread!! I can think of no reason as to why the answer isn't the same.
I'm putting a pier in my back yard (9x9" wood "box" made of 2x8's) and was looking for the pier top adapters. Came across a used CGE adapter plate on AstroM, but was missing the pier plate assembly that is normally sold with it that allows you to adjust tilt and azimuth. But since my mount has an azimuth and elevation adjustment, I was thinking, I really don't see the point. I have a means of attaching just the mount adapter plate directly to the top of the pier.
I'll assemble the whole thing and use a level when I pour the concrete to make it as level as possible, and I can always put thin washers between the plate and the top of the pier on the appropriate screw if I want to finesse levelness. It is not as convenient as having the adjustment screws accessible, but like, how often am I going to do this....?
So am I missing something here?