No, they are not the same thing, but rather than just removing the solenoid from the starter motor itself. Replace the whole thing.
A new starter solenoid itself worth as much as a second hand good condition starter motor with solenoid. So I don't see the fuzz why not just replace both of them since they are attached to each other.
I went through 2 starter solenoids since I had my 95 RAV4 and both times I just purchase something from a wrecker in good condition and to heck with the rest. Not to mention you can have spare parts for later.