Here is what I made in Adobe Pro:

The Tools Button:

The text field to populate with "Stamp":

I couldn't capture the UIs for this for some reason, so I chose Send Keys to navigate the stamp menu.
The full send keys: {Tab:4}{Space}{Down:2}{Right}{Down:3}{Enter} Note: 1000 milliseconds delay between keystrokes (it slows it down enough where it doesn't run over itself). You could probably get away with 100, but slower is safer.

The Document Button:

And then the last click I got from the recorder of placing it in the upper right corner, and it placed it exactly where I wanted. It was just a left click on the main document while recorder was running.
Best of luck!