Making mid-production changes in parts without changing the part number -- at least the customer-visible part number -- is not unheard-of, it's common.
Its not merely common its 'frustratingly common'.
I've experienced this time and again ordering replacement parts for a variety of cars. Usually the differences don't matter. The replacement is shaped a bit different, improved in some way, or the material is slightly different, the item has been cost reduced in some way perhaps, or suppliers were changed, and the part still works and still fits fine... but its not identical to the original.
That's generally not a big deal unless its a trip part. Then its maddening.
For example, I ordered a replacement rocker switch for my 911 power window some months ago, by part number. The part that arrived was in a slightly different finish -- the original was a glossy black plastic, the replacement was a slightly textured/matte black plastic. It was different, not merely "new" vs "showing some wear".
It fit and worked fine, but didn't match the switch for the passenger side window (which was right next to it on the drivers armrest) 100%.