The script step is called "Insert from Last Visited" and is compatible with iOS. An important thing to remember is the last record visited is the one that had a field clicked, not just a record that was viewed. Therefore, the step is often accompanied by a Go to Field step to select the current record first.
FileMaker Go does not have modifier keys like FileMaker Pro but there are a couple ways to solve this. You could use an OnModify script trigger that checks the first two characters type so if a user types something like xx (you define the combination you want to use in the script) the trigger can execute the Insert from Last Visited. Another option is to use custom menus to change the name of either the Add Record, Duplicate Record or Delete Record under Records on the menubar to Insert Previous. Then map the appropriate script to the command. The iPad keyboard will display the custom menu. A third option is to use a button to execute the script.