I have a similar situation (although not pickled). I picked up a stand and canopy, and I had to replace 2 sides of a stand. To keep it all looking the same, I skinned all of the visible sides on the stand. The canopy was fine.
What I am doing now, is sanding the base and canopy both. I will apply a layer of "Sand & Seal" per Jeff's recommendation on the whole thing and then I will stain it to a similar color as before (definitely not pickled) and then apply some clear coats to protect the finish.
I don't know how it will turn out, but atleast it should be even. My main concern will be the wood grain in the canopy. It's the original plywood and not skinned like the base, so the grain has become more visible.
I figure you will need to do something along these lines.
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