Join MCA. Your membership fee gets you access to their judging guides, which is as complete and up to date as you will find. The guides get updated whenever documentable exceptions are found. Part of the guides list acceptable finishes for a pretty large number of parts.
There are always exceptions. Lots of stuff happened on the line as cars were built. My 6 cylinder '71 convertible is a case in point. On the passenger side, there is a welded brace that was installed for higher displacement engines that was apparently cut off the car. The driver's side didn't have the brace welded on at all. So, either the car started out as a CJ and somebody changed the build order or somebody on the passenger side mixed up an order. My doors are also different. One side has a radius on the lower corner, the other side has a much crisper corner. Both doors are original to the car. Nothing you would notice unless you had the doors off side by side.