Checkbox selection model - check column header text

I have a checkbox selection model that I am using on a gridpanel. I have configured the CheckboxModel like so:

Ext.create('Ext.selection.CheckboxModel', {
    mode: 'Single',
    checkOnly: true,
    showHeaderCheckbox: false
});

This configuration allows the user to select only one record from the gridpanel. I have removed the checkbox in the header since I want the user to have to explicitly check the box in the record row. Now I have just a blank header in that column....is there any way to add text to that header column? From what I can tell it seems like my only options are to either leave the checkbox in the header or remove it and have a blank column header...is that correct?