The X5 has a third style of slide catch.
The original sits further back and was larger. The second style is further forward, lower profile, and was designed for use with a grip module that has a raised box around it to help prevent accidental manipulation.
The X grip will work with either of these styles and has a larger shelf that makes it pretty hard to accidentally hit the release. It ships with a forward swept slide catch that is as far forward as the newer design but has a profile size that's somewhere in between the other two. That's a good thing in my book since I find the thin profile one to be pretty sharp when not boxed in.