They're extremely close in their design, but they have a few key differences. The first and most notable difference is that they do not stack and lock into existing Apache racks.
However, if you mix and match the top and bottom of a Matsui rack with the top and bottom of an Apache rack, you can get them to stack and lock.
Aside from that, the Apache racks have those little risers inside too make the smaller chips fit a little better.