Good work on your part, finding the subtle differences. I should say at this point that I'm a well known UK Pro-Audio Consultant and Designer.
You have found subtle differences in the plastic moulding and the metal grille but these will NOT affect the sound in any way at all. I happen to have one of the cheap fakes and dismantled it to take a look inside.
The build quality was fine and it makes the same necessary connections to the 2 electret capsules. Now, most electret capsules are made on only a few production lines in Asia and are much of a muchness. I'm sure Sony don't make their own. In fact many Sony products today never even saw the inside of a Sony factory ! Sony, to be competitive, now use ODM (original design and manufacturing) outsourcing. For example, I have a 6 yr old Sony Premier Pro 23" LCD monitor which is as I recall simply a rebadged Samsung design (I have the service manual and it lists both Samsung and Sony part numbers). Makes sense since Samsung make a LOT of LCD screens.
To the point, The only difference in reality can be the microphone electret capsule. The plastic etc doesn't make a jot of difference.
If you're concerned, research electret mic capsules and find the best that will fit. Most likely Panasonic I think, dismantle and replace the capsules, an easy task for a hobbyist. You will now have the best mic of its type possible ! The capsules are insanely cheap too, so the original Sony item was vastly overpriced.