A 1996 manufacture date would not be a vintage MX Black, technically. They would be much closer to newer blacks than true vintage blacks.
Now, a 1986 manufacture date would be vintage MX Black for sure. And wouldn't you know it, my Wyse board? Yup. 1987 internal markings - so close enough! This is the original RJ11 board off a Wyse PC286, so guaranteed to be pre-1991.
- Cherries part of the logo slightly over the top rounded edge.
- "Cherry" branding vertically centered compared the the cherries using the small font.
- The keystem should rest naturally slightly HIGHER than the lip.
- Sharply defined bottom edge on top housing, rounded top edge.
- Flat stem.
- "Peaked" cutout. NOT rounded, there is a defined peak at the top of the stem.
So yes, Row 3 is vintage MX Black. On the Amiga example, the left is 'vintage' while the right has the later housing style. Every single MX Black on my Wyse keyboard here looks close to the OP's Row 3. OP's Row 3 looks like it has a sharper curve on the top than mine, but that may be lighting. Can't get good photos of it right now, but will be getting them at some point in the future.