Optical Illusion or Reality

I bought a YZ cam (according to official Yamaha part number) for my WR450F to change the timing to YZ. My mechanic who´s about the install the part says that he has compared the two parts (WR cam and new YZ cam) and say they are identical, just the dot is 1 tooth advanced. I told him that according to what I have read on this site the difference should be more, because simply advancing one tooth will disable the auto decompression for a 450 (different than the 400/426) He says that there is no optical difference to the position of the auto-decompression vs. the curve on the camshaft. Is this an optical illusion from my mechanic. I am afraid that I have bought the wrong cam than although the part number is the YZ one and the dot is one tooth advance. What should I do?

The YZ cam has a different length decompression pin to compensate for the change in timing. It's subtle but if you look closely you can visually see the difference.

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