When I search for SMD-7616 (or SMD-7613) on ni.com, it doesn't return any links to purchase them.
Have they been deprecated too?
What is an equivalent stepper drive now?
It appears that these motors do not have product pages. This is not uncommon -- not all of our products do. However, you can still purchase them from the 'Stepper and Servo Motor Motion Drive Device' page (link below).
Stepper and Servo Motor Motion Drive Device