The MPX 9700 / 10500 / 12500 / 15500 FIPS models are version of the "normal" Netscaler MPX 10500 / 12500 / 15500. The bigger numbers are upgraded versions)

You'll notice that, for the "normal" Netscaler range, there is no 9700, so the platform is known as the "MPX 10500". They added the MPX 9700 FIPS model to give a smaller FIPS unit - in a "normal" Netscaler you would you buy an MPX8005.

If you bought a "normal" MPX1550, then I suspect the hardware would also be identified as "MPX 10500"

is a FIPs version