So now I'm confused. You say your correct distributor number is 2875358. You have one with that PN stamped on it. The correct vacuum advance as per the parts book is 2875096. You have one with that PN stamped on it but it doesn't look like the illustration in the parts book. Does that about sum it up?

If so, I would assemble the distributor and use it. The stamped part numbers all agree with the parts book numerical listing and there is no reason I can see not to believe them. The illustrations in the parts books in the past with other components have been inaccurate, this may just be another case of that.