You can solve your problem by copying the code for the plain template. Create a custom template using it. Then delete these lines near the end, which produce the Paid in Full and Overdue stamps:
{% if emphasis.text != null and emphasis.positive %}
<tr><td colspan="99"><div style="text-align: center; margin-top: 40px"><span style="color: #006400; border-width: 5px; border-color: #006400; padding: 10px; font-size: 20px">{{ emphasis.text | upcase }}</span></div></td></tr>
{% endif %}
{% if emphasis.text != null and emphasis.negative %}
<tr><td colspan="99"><div style="text-align: center; margin-top: 40px"><span style="color: #FF0000; border-width: 5px; border-color: #FF0000; padding: 10px; font-size: 20px">{{ emphasis.text | upcase }}</span></div></td></tr>
{% endif %}
Or just copy and use one of the other templates. I haven’t checked every single one, but so far as I know, none of them include the stamps.